The standard reduction potentials for $M{n}^{3+}/M{n}^{2+}$ and $Mn{O}_2<mspace\; width="1em"></mspace>/M{n}^{3+}$ couples in acid medium at $25°C$ are 1.50 V and 1.00 V respectively. The following reaction:

$2M{n}^{3+}<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>2H_{2}O<mspace\; width="1em"></mspace>\to <mspace\; width="1em"></mspace>M{n}^{2+}<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>Mn{O}_2<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>4H^{+}<mspace\; width="1em"></mspace>is$

(1) reversible                                             

(2) non-spontaneous

(3) spontaneous                                         

(4) irreversible

1If a 100 mL solution of 0.1M HBr is titrated using a very concentrated solution of NaOH, when the conductivity (specific conductance) of the solution at the equivalence point will 3e (assume volume change is negligible due to addition of NaOH). Calculate your answer in terms of ${10}^{-1}S{m}^{-1},$

$\left[Given<mspace\; width="1em"></mspace>{{\wedge }^{°}}_{\left(N{a}^{+}\right)}=8\times {10}^{-3}S{m}^{2}mo{l}^{-1}<mspace\; width="1em"></mspace>{{\wedge }^{°}}_{\left(B{r}^{-}\right)}=4\times {10}^{-3}S<mspace\; width="1em"></mspace>m^2<mspace\; width="1em"></mspace>mo{l}^{-1}\right]$

(1) 6                               

(2) 12

(3) 15                             

(4) 24

In a half-cell containing $\left[T{l}^{3+}\right]<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>0.1<mspace\; width="1em"></mspace>M<mspace\; width="1em"></mspace>and<mspace\; width="1em"></mspace>[T{l}^{+}<mspace\; width="1em"></mspace>]<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>0.01<mspace\; width="1em"></mspace>M,$ the cell potential is – 1.2496 V for the reaction $T{l}^{+}\to <mspace\; width="1em"></mspace>T{l}^{3+}<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>2e^{-}$  The standard reduction potential of the $T{l}^{+}<mspace\; width="1em"></mspace>/T{l}^{3+}$ couple at $25°C$ is

(1) 1.44 V                                          

(2) 0.61 V

(3) 2.44 V                                          

(4) 1.22 V

In the following electrochemical cell, $M|M^{+}<mspace\; width="1em"></mspace>||<mspace\; width="1em"></mspace>X^{-}|X,$ the standard reduction potentials are $E{°}_{M+/M}=<mspace\; width="1em"></mspace>0.52<mspace\; width="1em"></mspace>V$ and $E{°}_{X/X^{-}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>0.42<mspace\; width="1em"></mspace>V<mspace\; width="1em"></mspace>at<mspace\; width="1em"></mspace>25°C.$ Which one of the following statements is correct ?

$\left(1\right)<mspace\; width="1em"></mspace>M<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>X<mspace\; width="1em"></mspace>\to <mspace\; width="1em"></mspace>M^{+}<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>X^{-}<mspace\; width="1em"></mspace>is<mspace\; width="1em"></mspace>spon\tan eous$              

$\left(2\right)<mspace\; width="1em"></mspace>M^{+}<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>X^{-}<mspace\; width="1em"></mspace>\to M<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>X<mspace\; width="1em"></mspace>is<mspace\; width="1em"></mspace>spon\tan eous$

$\left(3\right)<mspace\; width="1em"></mspace>E_{cell}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>0.77<mspace\; width="1em"></mspace>V$                                              

$\left(4\right)<mspace\; width="1em"></mspace>E_{cell}=<mspace\; width="1em"></mspace>–<mspace\; width="1em"></mspace>0.77<mspace\; width="1em"></mspace>V$

Given cell: 

Pt(s)|H₂(g)(P = 1 atm)| CH₃COOH(0.1 M), HCl(0.1 M) || KCl(aq)|Hg₂Cl₂(s)|Hg

EMF of the cell is found to be 0.045 V at 298 K and the temperature coefficient is 3.4×10^-4 V K^-1. The cell entropy change of the following cell is : 

[Given K_a CH₃COOH = 10^-5  M]

1. 70.8 J K⁻¹ mol⁻¹                      

2. 65.2 J K⁻¹ mol⁻¹

3. 79.2 J K⁻¹ mol⁻¹                  

4. 83.5 J K⁻¹ mol⁻¹

The reduction potential of a half-cell consisting of a Pt electrode immersed in $1.5<mspace\; width="1em"></mspace>M<mspace\; width="1em"></mspace>F{e}^{2+}$and $0.015<mspace\; width="1em"></mspace>M<mspace\; width="1em"></mspace>F{e}^{3+}$ solution at $25°C<mspace\; width="1em"></mspace>is<mspace\; width="1em"></mspace>\left(E_{\left(F{e}^{+3},<mspace\; width="1em"></mspace>Fe+2\right)}^{°}=+0.770<mspace\; width="1em"></mspace>v\right)$.

(1) 0.652 V                                                   

(2) 0.88 V

(3) 0.710 V                                                   

(4) 0.850 V

In a concentration cell, $Zn/Z{n}^{2+}<mspace\; width="1em"></mspace>(1.0<mspace\; width="1em"></mspace>M)<mspace\; width="1em"></mspace>\left|\right|<mspace\; width="1em"></mspace>Z{n}^{2+}<mspace\; width="1em"></mspace>(0.15<mspace\; width="1em"></mspace>M)/Zn$ as the cell discharges,

(1) reaction proceeds to the right

(2) the two solutions approach each other in concentration

(3) no reaction takes place

(4) water gets decomposed

A dilute solution of $H_2<mspace\; width="1em"></mspace>S{O}_4$ was electrolysed by passing a current of 2 amp. The time required for formation of 0.5 mole of oxygen is

(1) 26.8 hours                                    

(2) 13.4 hours

(3) 6.7 hours                                      

(4) 28.6 hours

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