online-test-on-electrochemistry.pdf

Chemistry - Electrochemistry [Time : 90 Mins]

TEST

[Max. Marks : 35]

Note : 1. Electrochemistry chapter Weightage total marks 5 2. There will be no overall option. 3. Internal choices (either/or type) on a very selective basis has been provided. This choice has been given in one question 2 of marks, one questions of 3 marks and all the three questions of 5 marks weight age.

1.

How many faradays of electricity are required to liberate 2 moles of hydrogen gas in electrolysis of a solution?

2.

Why does an alkaline medium inhibit the rusting of iron?

3.

Define electrochemical equivalent of a substance?

4.

Explain why:

5.

(i)

E0 for Mn3+/Mn2+ couple is more positive than that Fe3+/Fe2+. (At. No. Mn = 25, Fe = 26).

(ii)

Ce3+ can be easily oxidised to Ce4+ (At. No. Ce = 58).

Express the relationship between the degree of dissociation of an electrolyte and its molar conductivities.

6.

What is electrical conductance of electrolyte solution? Give its unit also.

7.

A solution of CuSO4 is electrolysed for 10 minutes with a current of 1.5 amperes. What is the mass of copper deposited at the cathode?

8.

What is Nernst equation ?

9.

Calculate molar conductance of acetic acid at infinite dilution from following values : −1

−2

−1

∞ (HCl) = 426.0 ohm cm mol , ∧m

−1

−2

∞ (CH3COONa) = 91.0 ohm cm mol ∧m

and

−1

−2

−1

∞ (NaCl) = 126.0 ohm cm mol ∧m

−1

10.

Derive relation between standard electromotive force and equilibrium constant.

11.

Write the symbolic representation of the electro-chemical cell with the cell-reaction:

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Zn(s) + 2Ag+(aq) → Zn2+

(aq)

+ 2Ag(s). Indicate the oxidation electrode and the direction of the

movement of electrons and write the electrode reactions?

12.

What is specific conductivity? Give its unit.

13.

Calculate the potential (emf) of the cell Cd | Cd2+ (0.10M) || H+(0.20M)|Pt, H2 (0.5 atm) (Given E° for Cd2+ /Cd = - 0.403 V, R = 8.314 JKT-1 mol-1, F = 96,00 C mol-1).

14.

Explain Kohlrausch's law of independent migration of ions. Mention one application of Kohlrausch's law?

15.

What is standard hydrogen electrode? Explain with diagram.

16.

Draw a labelled diagram of electrochemical cell and write cell reaction. Write two main functions of salt bridge.

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