The volume of gases liberated at STP when a charge of 2F is passed through aqueous solution of sodium phosphate, is :

1. 11.2L                                           

2. 44.8L

3. 33.6L                                           

4. 22.4L

The $E°$ in the given diagram is,
(1) 0.5                                     

(2) 0.6

(3) 0.7                                    

(4) 0.8

The temperature coefficient of a standard Cd-cell is $–5.0 \times {10}^{-5} V{k}^{-1}$ whose emf at $25°C$ is 1.018 V. During the cell operation, the temperature will -

(1) increase                                      

(2) decreases

(3) either                                         

(4) remains constant

Na-amalgam is prepared by electrolysis of NaCl solution using liquid Hg as a cathode. How

long should the current of 10 amp. is passed to produce 10% Na – Hg on a cathode of 10

gm Hg. (atomic mass of Na = 23).

(A) 7.77 min.                                               

(B) 9.44 min.

(C) 5.24 min.                                               

(D) 11.39 min.

The $k=$ $4.95$ $\times$ ${10}^{-5}S$ $c{m}^{-1}$ for a 0.00099 M solution. The reciprocal of the degree of dissociation of acetic acid, if ${\wedge }_m^0$ for acetic acid is 400 S $c{m}^{2}mo{l}^{-1}$ will be:

A resistance of 50$\Omega$ is registered when two electrodes are suspended into a beaker containing a dilute solution of a strong electrolyte such that exactly half of the them are submerged into solution. If the solution is diluted by adding pure water (negligible conductivity) so as to just completely submerge the electrodes, the new resistance offered by the solution would be

(1) \(50 \Omega\)                                       

(2) \(100   \Omega\)

(3) \(25 \Omega\)                                       

(4) \(200 \Omega\)

The magnitude of the emf of the following cell \(at ~25^{\circ} \mathrm{C} \) is:
\(P t\left(H_2\right) \mid 0.1 M\text{ acetic acid+ 0.1 M sodium acetate} ~\\\| ~0.1 \mathrm{M}\text{ formic acid + 0.1 M}\text{ sodium formate} \mid P t\left(H_2\right) \)

\( \left(\text { Use } K_{a(\text { acetic acid })}=1.8 \times 10^{-5} \text { and } K_{a(\text { Formic acid })} \\=2.1 \times 10^{-4}\right)\) 
1. 0.0315 volt
2. 0.0629 volt
3. 0.0455 volt
4. 0.0545 volt

A flashlight cell has the cathodic reaction $2Mn{O}_2 \left(s\right) + Z{n}^{+2}+ 2\text{'}{e}^{-}\to Zn M{n}_2{O}_4 \left(S\right)$

If the flashlight cell is to give out 4.825 mA, how long could it run if initially 8.7 g of the

limiting reagent $Mn{O}_2$ is present? [Mn = 55, O = 16]

(1) $2 \times {10}^{6}sec$                                         

(2) $4 \times {10}^{6}sec$

(3) $6\times {10}^{6}sec$                                          

(4) $8 \times {10}^{6}sec$

In acidic medium $Mn{O_4}^{-}$ is an oxidising agent. $Mn{O_4}^{-} + 8H^{+} + 5e^{-} \to M{n}^{2+} + 4H_{2}O. If H^{+}$ ion concentration is doubled, electrode potential of the half cell will : 

(1) Increase by 28.46 mV                             

(2) Decrease by 28.46 mV

(3) Increase by 14.23 mV                             

(4) Decrease by 142.30 mV

The reduction potential of a half-cell consisting of a Pt electrode immersed in $1.5 M F{e}^{2+}$and $0.015 M F{e}^{3+}$ solution at $25°C is \left(E_{\left(F{e}^{+3}, Fe+2\right)}^{°}=+0.770 v\right)$.

(1) 0.652 V                                                   

(2) 0.88 V

(3) 0.710 V                                                   

(4) 0.850 V