JAMB 2019 Chemistry Past Questions and Answers Online Practice
Study the following JAMB 2019 Chemistry Past Questions and Answers if you’re taking part in this year’s UTME.
NOTE: In this Chemistry Past Question & Answers Quiz;
raised to power will be denoted as ^ (i.e 4 raised to power 2 is written as 4^2).
subscript will be denoted to ~ (i.e 4 subscript 2 is written as 4 ~ 2).
Do you understand? Now start…
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1 A second alkanol can be oxidized to give an __________
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alkanone
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alkyne
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alkanoic acid
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alkanal
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2 Which of the following will give a precipitate with an aqueous solution of copper (I) chloride?
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But-2-ene
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But-1-ene
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But-2-yne
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But-1-yne
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3 The IUPAC name for CH~3CH~2COOCH~2CH~3 is
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methylpropanoate
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ethylethanoate
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ethylpropanoate
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methylethanoate
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4 A certain hydrocarbon on complete combustion at s.t.p produced 89.6dm^3 of CO~2 and 54g of water. The hydrocarbon should be
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C~6H~6
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C~4H~10
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C~5H~10
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C~4H~6
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5 2-methylprop-1-ene is an isomer of
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3-methyl but-1-ene
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2-methyl but-1-ene
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but-2-ene
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pent-2-ene
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6 Hydrocarbons which will react with Tollen's reagent conform to the general formula
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C~nH~n
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C~nH~(2n+2)
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C~nH~(2n-2)
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C~nH~(2n+1)OH
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7 The IUPAC name of the compound CF~3CHBrCl is
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2-chloro-2-bromo-1,1,1-trifluoroethane
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2-bromo-2-chloro-1,1,1-trifluoroethane
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1-bromo-1-chloro-2,2,2-trifluoroethane
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1,1,1-trifluoro-2-bromo-2-chloroethane
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8 Synthetic rubber is obtained from the polymerization of
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neoprene
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isoprene
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butandiene
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propylene
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9 Burning magnesium ribbon in air removes which of the following?
(i) oxygen
(ii) nitrogen
(iii) argon
(iv) carbon(iv)oxide
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i and iv only
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i, ii, iii and iv only
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i only
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i and ii only
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10 Which of the following is the best starting material for the preparation of oxygen? Heating of trioxonitrate (v) with _________
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Pb
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Zn
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Ca
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Na
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11 Which of the following metals is the most essential in the regulation of blood volume, blood pressure and osmotic equilibrium?
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Zinc
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Manganese
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Sodium
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Iron
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12 Which of the following alkaline metals react more quickly spontaneously with water?
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Calcium
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Beryllium
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Magnesium
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Strontium
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13 When chlorine water is exposed to bright sunlight, the following products are formed
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HCl~(aq) and Cl~2
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HOCl~aq and Cl~2
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HCl~(aq) and O~2
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HOCl~(aq) and O~2
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14 Which process(es) is/are involved in the turning of starch iodide paper blue-black by chlorine gas?
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chlorine attacks the starch to give the blue-black color
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chlorine attacks the iodide ion to give the blue-black color
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chlorine oxidizes the iodide ion to produce iodine which attacks the starch to give the blue-black color
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iodine attacks the starch to give the blue-black color
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15 Which of the following is a set of neutral oxides?
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N~2O, H~2O, CO
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N~2O, SO~2, CO
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N~2O, Na~2O, ZnO
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N~2O, SO~3, NO
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16 SO~3 is not directly dissolved in water in the industrial preparation of H~2SO~4 by the contact process because
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SO~3 is an acidic gas
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Acid is usually added to water and not water to acid
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The reaction between SO~3 and water is violently exothermic
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SO~3 does not dissolve readily in water
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17 Which of the following statements does not show Rutherford's account of Nuclear Theory? An atom contains a region ____________
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which contains protons and neutrons
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which is positively charged
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which is massive and can cause deflection of a few projectiles
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which is very large and in which close to 98% of projectiles pass undeflected
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18 Elements X and Y have electronic configurations 1s^2 2s^2 2p^4 and 1s^2 2s^2 2p^6 3s^2 3p^1 respectively. When they combine, the formula of the compound formed is
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XY
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X~2Y
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Y~2X~3
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X~2Y~3
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19 By what amount must the temperature of 200cm^3 of Nitrogen at 27°C be increased to double the pressure if the final volume is 150cm^3 (Assume ideality)
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150°C
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177°C
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71°C
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120°C
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20 The combustion of carbon(ii)oxide in oxygen can be represented by equation. 2CO + O~2 → 2CO~2. Calculate the volume of the resulting mixture at the end of the reaction if 50cm~3 of carbon(ii)oxide was exploded in 100cm~3 of oxygen
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75cm^3
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125cm^3
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100cm^3
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50cm^3
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21 When ammonia and hydrogen ion bond together to form ammonium ion, the bond formed is called
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electrovalent bond
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co-ordinate bond
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ionic bond
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covalent bond
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22 Which of the following represents the kind of bonding present in ammonium chloride?
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ionic only
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covalent only
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ionic and dative covalent
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dative covalent
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23 Consider the reaction A~(s) + 2B~(g) → 2C~(aq) + D~(g). What will be the effect of a decrease in pressure on the reaction?
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the equilibrium will shift
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rate of forward reaction will increase
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rate of backward reaction will increase
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rates of forward and backward reaction are not affected
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24 For the general equation of the nature xP + yQ ⇌ mR + nS, the expression for the equilibrium constant is
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k[P]^x [Q]^y
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(m[R][S]) / (x[P]y[Q])
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([P]^x[Q]^y) / ([R]^m[S]^n)
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([R]^m[S]^n) / ([P]^x[Q]^y)
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25 Which of the following reactions is an oxidation process?
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2H^+ + 2e− → H~2
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2O^2 + 4e O~2
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OCl^− + H2O + 2e^− → 2OH^− + Cl^−
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Cl + e^− → Cl^−
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26 If acidified Potassium Dichromate(VI) (K^2Cr^2O^7) acts as oxidizing agent, color changes from
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yellow to green
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orange to green
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yellow to red
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orange to red
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27 The heat of formation of ethene, C^2H^4 is 50 kJmol^-1, and that of ethane, C~2H~6 is -82kJmol^-1. Calculate the heat evolved in the process: C~2H~4 + H~2 → C~2H~6
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-122kJ
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-132kJ
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-88kJ
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-60kJ
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28 Which of the following statements about catalyst is false?
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biological catalysts are called enzymes
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catalyst do not appear in the balanced equation
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catalyst reduce the activation energy for a reaction
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catalysts do not alter the mechanism of the reaction and never appear in the rate low
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29 Which of the following does not support the fact that air is a mixture?
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the constituents of air are in a fixed proportion by mass
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it cannot be represented with a chemical formula
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the constituents of air can be separated by physical by physical means
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none of the above
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30 What technique is suitable for separating a binary solution of potassium chloride and potassium trioxochlorate (V)?
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Fractional crystallization
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Fractional distillation
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Filtration
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Evaporation
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31 At 27°C, 58.5g of sodium chloride is present in 250cm^3 of a solution. The solubility of sodium chloride at this temperature is? (molar mass of sodium chloride = 111.0gmol^-1)
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2.0 moldm^-3
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0.25 moldm^-3
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1.0 moldm^-3
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0.5 moldm^-3
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32 Which of the following properties increases from left to right along the period but decreases down the group in the Periodic Table?
i. Atomic Number
ii. Ionization energy
iii. Metallic character
iv. Electron affinity
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ii and iii only
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ii and iv only
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iii and iv only
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i and ii only
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33 The molecular shape and bond angle of water are respectively
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linear, 180°
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bent, 109.5°
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tetrahedral, 109.5°
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bent, 105°
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34 Na~2 CO~3 + 2HCl 2NaCl + H~2O + CO~2. The indicator most suitable for this reaction should have a pH equal to
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5
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7
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3
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9
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35 A radioactive nucleus has a half-life of 20 years, starting with 100,000 particles, how many particles will be left exactly at the end of 40 years
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75,000 particles
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35,000 particles
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25,000 particles
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50,000 particles
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36 Which two gases can be used for the demonstration of the fountain experiment?
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SO^3 and NH^3
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SO^2 and NH^3
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HCl and NH^3
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SO^2 and HCl
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37 Which of the following pollutants will lead to the depletion of ozone layer?
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chlorofluorocarbon
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carbon (ii) oxide
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hydrogen sulphide
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sulphur (iv) oxide
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38 Which of the following describes the chemical property of acids?
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None of the above
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Acid + XCO~3 Salt + H~2O + NH~3
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Acid + NaOH Normal salt + CO~2
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Acid + X^nCO^3 Salt + H^2O + CO^2
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39 Which of the following pairs cannot be represented with a chemical formula?
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air and bronze
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bronze and sodium chloride
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copper and sodium chloride
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caustic soda and washing soda
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40 Consider the equation below:
The oxidation number of chromium changes from?
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+5 to +3
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+6 to +3
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-2 to +3
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+7 to +3
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41 Which of the following is a physical change?
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Exposing white phosphorus to air
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Burning kerosene
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Dissolving calcium in water
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Freezing ice cream
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42 In the reaction between sodium hydroxide and tetraoxosulphate (VI) solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralize 10cm^3 of 1.25 molar tetraoxosulphate (vi) acid?
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25cm^3
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10cm^3
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20cm^3
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50cm^3
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43 Sulphur exists in six forms in the solid state. This property is known as
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Isomerism
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Allotropy
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Isotopy
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Isomorphism
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44 In the reaction below:
M + N → P
ΔH = +Q kJ
Which of the following would increase the concentration of the product?
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Adding a suitable catalyst
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Increasing the concentration of P
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Increasing the temperature
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Decreasing the temperature
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45 A compound contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180. Find the molecular formula. [H = 1, C = 12, O = 16]
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C~3H~6O~3
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C~6H~6O~3
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C~6H~12O~6
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CH~2O
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46 The IUPAC nomenclature of the compound
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3,4- dimethylhexane
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2,3- dimethyl pentane
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2- ethyl hexane
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2,3- dimethylhexane
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47 Which of the following gases contains the least number of atoms at s.t.p?
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1 mole of butane
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4 mole of butane
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3 mole of butane
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7 mole of butane
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48 What mass of magnesium would be obtained by passing a current of 2 amperes for 2 hours 30 mins, through molten magnesium chloride? [1 faraday = 96500C, Mg = 24]
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1.12g
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4.48g
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1.80g
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2.00g
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49 Which important nitrogen-containing compound is produced in Haber's process?
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NH~3
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NO~2
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NO
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HNO~3
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50 Elements in the periodic table are arranged in the order of their
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atomic numbers
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metallic character
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mass number
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relative atomic mass
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51 What volume of 0.100M sodium trioxonitrate (V) solution contains 5g of solute. [Na = 23, N = 14, O = 16]
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1.7 litres
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0.420 litres
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0.588 litres
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2.35 litres
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52 The two ions responsible for hardness in water are
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Ca^2+ and/or Mg^2+
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K and Mg^2+
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Ca^2+ and/or Li^+
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Ca and / or Na~2
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53 Which of the following could not be alkane?
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C~4H~10
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C~5H~12
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C~7H~14
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C~8H~18
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54 The electronic configuration of element Z is:
What is the formula of the compound formed between Z and tetraoxosulphate (VI) ion?
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Z~3(SO~4)~2
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ZSO~4
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Z~2 SO~4
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Z~2(SO~4)~3
Correct!Wrong! -
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55 The hybridization in the compound in the equation below is?
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sp^3 and sp
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sp
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sp^2
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sp^3 and sp^2
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56 The following are isoelectronic ions except
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Na+
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Mg^2+
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Si^2+
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O^2+
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57 Consider the reaction below:
What will be the effect of decrease in temperature on the reaction?
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Rate of backward reaction will increase
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The equilibrium constant will shift
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Rates of forward and backward reactions are not affected
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Rate of forward reaction will increase
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58 A cell shorthand notation can be written as A / A + // B^2 + /B. The double slash in the notation represents the
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electrolyte
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electrodes
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salt bridge
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solid - liquid interface
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59 The shapes of water, ammonia, carbon (iv) oxide and methane are respectively
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linear, tetrahedral, angular and pyramidal
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angular, pyramidal, linear and tetrahedral
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pyramidal, linear, tetrahedral and angular
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tetrahedral, angular, pyramidal and linear
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60 Which quantum divides shells into orbitals?
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spin
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principal
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Azimuthal
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Magnetic
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61 The oxidation state(s) of nitrogen in ammonium nitrite is/are
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-3, +3
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+5
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-3, +5
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-3
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62 Hydrogen bond is a sort of
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van der waals force
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dative bond
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ionic bond
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a covalent bond
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63 Methane is prepared in the laboratory by heating a mixture of sodium ethanoate with soda lime. The chemical constituent(s) of soda lime is/are
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Ca(OH)~2 and NaOH
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Na~2CO~3
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NaCl
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NaOH
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64 Which of the following sets of operation will completely separate a mixture of sodium chloride, sand and iodine?
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addition of water, filtration, evaporation to dryness and sublimation
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filtration, evaporation to dryness, addition of water and sublimation
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sublimation, filtration, evaporation and addition of water
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sublimation, addition of water, filtration and evaporation to dryness
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65 200cm^3 of 0.50mol/dm^3 solution of calcium hydrogen trioxocarbonate (IV) is heated. The maximum weight of solid precipitated is
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10g
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25g
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22g
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15g
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66 Which of the following conditions will most enhance the spontaneity of a reaction?
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△H is negative and greater than T△S
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△H is negative and △S = 0
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△H is positive and less than T△S
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△H is positive and equal to T△S
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67 X is a substance which liberates CO~2 on treatment with concentrated H~2SO~4 . A warm solution of X can decolorize acidified KMnO~4 . X is
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HCOOH
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NaHCO~3
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FeCO~3
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H~2C~2O~4
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68 The velocity, V of a gas is related to its mass, M by (k = proportionality constant)
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V = k/M
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V = k/M^½
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V = kM²
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V = (k/M)^½
Correct!Wrong! -
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69 The oxidation state(s) of nitrogen in ammonium nitrite is/are
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-3, +5
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+5
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-3, +3
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-3
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70 Hydrogen diffused through a porous plug
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thrice as fast as oxygen
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at the same speed as oxygen
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four times as fast as oxygen
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twice as fast as oxygen
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71 If the cost of electricity required to discharge 10g of an ion X³ is N20.00, how much would it cost to discharge 6g of ion Y² ? [1 faraday = 96,500C, atomic masses are X = 27, Y = 24]
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N10.00
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N6.00
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N20.00
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N9.00
Correct!Wrong! -
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72 The cost of discharging 6.0g of a divalent metal, X from its salt is ₦12.00. What is the cost of discharging 9.0g of a trivalent metal, Y from its salt under the same condition? [X = 63, Y = 27, 1F = 96,500C]
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N12.00
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N27.00
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N63.00
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N95.00
Correct!Wrong! -
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73 How many alkoxyalkanes can be obtained from the molecular formula C~4H~10O?
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4
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2
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1
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3
Correct!Wrong! -
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74 The reaction below is?
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not a redox reaction because there is no oxidant in the reaction
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not a redox reaction because there is no reductant in the reaction
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a redox reaction in which H~2S is the oxidant and SO~2 is the reductant
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a redox reaction in which SO~2 is the oxidant and H~2S is the reductant
Correct!Wrong! -
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75 When ammonia and hydrogen ion bond together to form ammonium ion, the bond formed is called
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electrovalent bond
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co-ordinate bond
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ionic bond
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covalent bond
Correct!Wrong! -
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