Electrochemistry · Question 21

For the cell reaction 2Fe3+(aq) + 2I-(aq) 2Fe2+(aq) + I2(aq) E cell = 0.24 V at 298 K. The standard Gibbs energy ( r G ) of the cell reaction is : [Given that Faraday constant F = 96500 C mol-1]

1. 46.32 kJ mol-1
2. 23.16 kJ mol-1
3. -46.32 kJ mol-1
4. -23.16 kJ mol-1

In the electrochemical cell : Zn | ZnSO4 (0.01 M) || CuSO4 (1.0 M) | Cu, the emf of this Daniell cell is E1. When the concentration of ZnSO4 is changed to 1.0 M and that of CuSO4 changed to 0.01 M, the emf changes to E2. From the following, which one is the relationship between E1 and E2? (Given, 2.303RTF = 0.059)

1. E1 < E2
2. E1 > E2
3. E2 = 0 E1
4. E1 = E2

The pressure of H2 required to make the potential of H2-electrode zero in pure water at 298 K is

1. 10-10 atm
2. 10-4 atm
3. 10-14 atm
4. 10-12 atm

The molar conductivity of a 0.5 mol/dm3 solution of AgNO3 with electrolytic conductivity of 5.76 10-3 S cm-1 at 298 K is

1. 2.88 S cm2/mol
2. 11.52 S cm2/mol
3. 0.086 S cm2/mol
4. 28.8 S cm2/mol

During the electrolysis of molten sodium chloride, the time required to produce 0.10 mol of chlorine gas using a current of 3 amperes is

1. 55 minutes
2. 110 minutes
3. 220 minutes
4. 330 minutes

If the E cell for a given reaction has a negative value, which of the following gives the correct relationships for the values of G and Keq ?

1. G > 0; Keq < 1
2. G > 0; Keq > 1
3. G < 0; Keq > 1
4. G < 0; Keq < 1

The number of electrons delivered at the cathode during electrolysis by a current of 1 ampere in 60 seconds is (charge on electron = 1.60 10-19 C)

1. 6 1023
2. 6 1020
3. 3.75 1020
4. 7.48 1023

Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because

1. zinc is lighter than iron
2. zinc has lower melting point than iron
3. zinc has lower negative electrode potential than iron
4. zinc has higher negative electrode potential than iron

Aqueous solution of which of the following compounds is the best conductor of electric current ?

1. Hydrochloric acid, HCl
2. Ammonia, NH3
3. Fructose, C6H12O6
4. Acetic acid, C2H4O2

A device that converts energy of combustion of fuels like hydrogen and methane, directly into electrical energy is known as

1. dynamo
2. Ni-Cd cell
3. fuel cell
4. electrolytic cell