Electrochemistry Practice Test with Answers:
Ques. How many Faradays are required to generate one gram atom of magnesium from MgCl2
(a) 1
(b) 2
(c) 3
(d) 4
Ques. A solution of a salt of a metal was electrolysed for 150 minutes with a current of 0.15 amperes. The weight of metal deposited was 0.783 gm. The equivalent weight of the metal is
(a) 55.97 gm
(b) 65.97 gm
(c) 75.97 gm
(d) 85.97 gm
Ques. Beryllium is placed above magnesium in the second group. Beryllium dust, therefore when added to MgCl2 solution will
(a) Have no effect
(b) Precipitate Mg metal
(c) Precipitate MgO
(d) Lead to dissolution of Be metal
Ques. What is the standard cell potential for the cell
Zn / Zn2+ (1M) || Cu2+ (1M) / Cu
Eo for Zn / Zn2+ (1M) = –0.76 V & Cu2+ / Cu = + 0.34 V
(a) –0.76 + (–0.34) = 0.42 V
(b) –0.34 + 0.76 = +0.42 V
(c) 0.34 – (0.76) = 1.10 V
(d) –0.76 – (+0.34) = –1.10 V
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Ques. In Cu – Zn cell
(a) Reduction occurs at the copper cathode
(b) Oxidation occurs at the copper cathode
(c) Reduction occurs at the anode
(d) Chemical energy is converted to light energy
Ques. Normal aluminium electrode coupled with normal hydrogen electrode gives an emf of 1.66 volts. So the standard electrode potential of aluminium is
(a) – 1.66 V
(b) + 1.66 V
(c) – 0.83 V
(d) + 0.83 V
Ques. The conductivity of strong electrolyte is
(a) Increase on dilution slightly
(b) Decrease on dilution
(c) Does not change with dilution
(d) Depend upon density of electrolytes itself
Ques. During the electrolysis of an electrolyte, the number of ions produced, is directly proportional to the
(a) Time consumed
(b) Electro chemical equivalent of electrolysis
(c) Quantity of electricity passed
(d) Mass of electrons
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Ques. The amount of silver deposited by passing 241.25 coulomb of current through silver nitrate solution is
(a) 2.7 g
(b) 2.7 mg
(c) 0.27 g
(d) 0.54 g
Ques. When the sample of copper with zinc impurity is to be purified by electrolysis, the appropriate electrodes are Cathode – Anode
(a) Pure zinc – Pure copper
(b) Impure sample – Pure copper
(c) Impure zinc – Impure sample
(d) Pure copper – Impure sample
Ques. The number of coulombs required for the deposition of 107.870 g of silver is
(a) 96,500
(b) 48,250
(c) 1,93,000
(d) 10,000
Ques. In the electrolytic cell, flow of electrons is from
(a) Cathode to anode in solution
(b) Cathode to anode through external supply
(c) Cathode to anode through internal supply
(d) Anode to cathode through internal supply
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Ques. On passing 0.5 faraday of electricity through NaCl, the amount of Cl deposited on cathode is
(a) 35.5 gm
(b) 17.75 gm
(c) 71 gm
(d) 142 gm
Ques. The standard EMF for the given cell reaction Zn + Cu2+ = Cu + Zn2+ is 1.10 V at 25o C. The EMF for the cell reaction, when 0.1 M Cu2+ and 0.1 M Zn2+ solutions are used, at 25o C is
(a) 1.10 V
(b) 0.110 V
(c) –1.10 V
(d) –0.110 V
Ques. Which of the following shows electrical conduction?
(a) Potassium
(b) Graphite
(c) Diamond
(d) Sodium
Ques. Which of the following will not conduct electricity in aqueous solution?
(a) Copper sulphate
(b) Sugar
(c) Common salt
(d) None of these
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Ques. The amount of ion discharged during electrolysis is not directly proportional to
(a) Resistance
(b) Time
(c) Current
(d) Chemical equivalent of the ion
Ques. Which of the following liberate hydrogen on reaction with dilute H2SO4
(a) Fe
(b) Cu
(c) Al
(d) Hg
Ques. Amount of electricity that can deposit 108 gm of silver from AgNO3 solution is
(a) 1 ampere
(b) 1 coulomb
(c) 1 faraday
(d) None of these
