If an iron rod is dipped in CuSO₄ solution, then:

1. Blue colour of the solution turns red.

2. Brown layer is deposited on iron rod.

3. No change occurs in the colour of the solution.

4. None of the above.

A depolariser used in dry cell batteries is: 

1. Ammonium chloride 

2. Manganese dioxide

3. Potassium hydroxide 

4. Sodium phosphate

A certain current liberates 0.504 g of hydrogen in 2 hr. How many gram of copper can be liberated by the same current flowing for the same time in CuSO₄ solution?

1. 12.7

2. 16

3. 31.8

4. 63.5

What happens to the voltage in a galvanic cell when the salt bridge is removed?

1. The voltage drops to zero.
2. The voltage remains the same.
3. The voltage gradually increases.
4. The voltage rapidly increases.

When NaCl solution is electrolysed using Pt electrodes then pH of solution

1. Increases

2. Decreases

3. Remains same

4. Firstly increases and then decreases

The quantity of electricity required to reduce 12.3 g of nitrobenzene to aniline with 50 % current efficiency is:

1. 1 F

2. 0.6 F

3. 0.5 F

4. 1.2 F

Electrolysis of hot aqueous solution of NaCl gives NaClO₄ as-

$\mathrm{NaCl} +\hspace{0.17em}4{\mathrm{H}}_2\mathrm{O} \stackrel{ }{\to }{\mathrm{NaClO}}_4 + 4{\mathrm{H}}_2$

How many faraday are required to obtain 1000 g of sodium perchlorate ?

(1) 66 F

(2) 122.5 F

(3) 15.13 F

(4) 1.86 F

A button cell used in watches functions as following

Zn(s) + Ag₂O(s) + H₂O (l) $\rightleftharpoons$2Ag(s) + Zn²⁺(aq) + 2OH^-(aq)

If half cell potentials are

$$\begin{gathered} {{\mathrm{Zn}}^{2+}}_{\left(\mathrm{aq}\right)} +\hspace{0.17em}2{\mathrm{e}}^{-} \to {\mathrm{Zn}}_{\left(\mathrm{x}\right)}; {\mathrm{E}}^{\mathrm{o}} = -0.76\mathrm{V} \\ {\mathrm{Ag}}_2{\mathrm{O}}_{\left(\mathrm{s}\right)} + {\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)} + 2{\mathrm{e}}^{-} \to 2{\mathrm{Ag}}_{\left(\mathrm{s}\right)} + 2{{\mathrm{OH}}^{-}}_{\left(\mathrm{aq}\right)}; \\ {\mathrm{E}}^{\mathrm{o}} = 0.34\mathrm{V} \end{gathered}$$

The cell potential will be

1. 0.84 V

2. 1.34 V

3. 1.10 V

4. 0.42 V

Limiting molar conductivity of NH₄OH (i.e Åm(NH₄OH)) is equal to:-

1. Å_m (NH₄Cl)+Å_m(NaCl)-Å_m(NaOH) 

2. Å_m(NaOH)+Å_m(NaCl)-Å_m(NH₄Cl)

3. Å_m(NH₄OH)+Å_m(NH₄Cl)-Å_m(HCl)

4. Å(NH₄Cl)+Å(NaOH)-Å(NaCl)

The efficiency of a fuel cell is given by:

$\left(\mathrm{a}\right) ∆\mathrm{H}/∆\mathrm{G} \left(\mathrm{b}\right) ∆\mathrm{G}/∆\mathrm{S}$
$\left(\mathrm{c}\right) ∆\mathrm{G}/∆\mathrm{H} \left(\mathrm{d}\right) ∆\mathrm{S}/∆\mathrm{G}$