Three moles of electrons are passed through three solutions in succession containing ${\mathrm{AgNO}}_3,{\mathrm{CuSO}}_4$ and ${\mathrm{AuCl}}_3$, respectively. The molar ratio of amounts of cations reduced at cathode will be

The following reaction takes place at $25°\mathrm{C}$.

$\mathrm{Sn} \left(\mathrm{s}\right) + {\mathrm{Pb}}^{2+}\left(\mathrm{aq}\right)\to {\mathrm{Sn}}^{2+}\left(\mathrm{aq}\right) + \mathrm{Pb} \left(\mathrm{s}\right); {\mathrm{E}}_{\mathrm{cell}}^0 =0.01 \mathrm{V}$

If an excess of tin metal is added to $1.0 \mathrm{M} {\mathrm{Pb}}^{2+}$, what is the concentration of ${\mathrm{Pb}}^{2+}$at equilibrium?

Answer correct up to one place of decimal.

Calculate the equilibrium constant for the reaction $2{\mathrm{Fe}}^{3+}+3{\mathrm{I}}^{-}\rightleftharpoons 2{\mathrm{Fe}}^{2+}+{\mathrm{I}}_3^{-}$. The standard reduction potentials in acidic-medium conditions are $0.77$and $0.54 \mathrm{V}$ respectively for ${\mathrm{Fe}}^{3+}/{\mathrm{Fe}}^{2+}$ and ${\mathrm{I}}_3^{-}/{\mathrm{I}}^{-}$ couples.

If the answer is of type $\mathrm{y}\times {10}^7$, report the value of $\mathrm{y}$ correct up to the nearest integer.

In the following process of disproportionation,

${\underset{\begin{array}{c}\mathrm{Chlorate}\\ \mathrm{ion}\end{array}}{2{\mathrm{ClO}}_3^{-}}⟶{\mathrm{ClO}}_2^{-}+\underset{\begin{array}{c}\mathrm{Perchlorate}\\ \mathrm{ion}\end{array}}{{\mathrm{ClO}}_4^{-}}}_{{\mathrm{E}}_{\frac{{\mathrm{ClO}}_3^{-}}{{\mathrm{ClO}}_2^{-}}}^{°}=+0.33 \mathrm{V}}^{{\mathrm{E}}_{\frac{{\mathrm{ClO}}_4^{-}}{{\mathrm{ClO}}_3^{-}}}^{°}=+0.36 \mathrm{V}}$

Initial concentration of chlorate ion was $0.1 \mathrm{M}$. The equilibrium concentration of per chlorate ion will be $1.9\times {10}^{-\mathrm{x}}$. Hence $\mathrm{x}$ is $\frac{2.303 \mathrm{RT}}{\mathrm{nF}}=0.06$

${\mathrm{H}}_2\left(\mathrm{g}\right)+\frac{1}{2}{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) ; {\mathrm{E}}_{\mathrm{cell} }^0=1.23 \mathrm{V}$

${\left({\mathrm{\Delta }}_{\mathrm{f}}\mathrm{H}\right)}_{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)}=-245 \mathrm{kJ} {\mathrm{mol}}^{-1},{\mathrm{\Delta }}_{\mathrm{vap}}\mathrm{H}\left({\mathrm{H}}_2\mathrm{O},\mathrm{l}\right)=40 \mathrm{kJ} {\mathrm{mol}}^{-1}$

$\log 2=0.3,\frac{2.303\mathrm{RT}}{\mathrm{F}}=0.06$

The efficiency of fuel cell is _____ percent(97.9/82.68/92.70).

Consider a $70\%$ efficient hydrogen - oxygen fuel cell working under standard conditions at $1$ bar and $298 \mathrm{K}$. Its cell reaction is

${\mathrm{H}}_2\left(\mathrm{g}\right)+\frac{1}{2}{\mathrm{O}}_2\left(\mathrm{g}\right)⟶{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

The work derived from the cell on the consumption of $2.0\times {10}^{-3} \mathrm{mol}$ of ${\mathrm{H}}_2\left(\mathrm{g}\right)$ is used to compress $1.00 \mathrm{mol}$ of a monoatomic ideal gas in a thermally insulated container. What is the change in the temperature (in $\mathrm{K}$) of the ideal gas?

The standard reduction potentials for the two half - cells are given below

${\mathrm{O}}_2\left(\mathrm{g}\right)+4{\mathrm{H}}^{+}\left(\mathrm{aq}\right)+4{\mathrm{e}}^{-}⟶2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right), \mathrm{E}°=1.23 \mathrm{V}.$

$2{\mathrm{H}}^{+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}⟶{\mathrm{H}}_2\left(\mathrm{g}\right), \mathrm{E}°=0.00 \mathrm{V}$

Use $\mathrm{F}=96500{\mathrm{Cmol}}^{-1},\mathrm{R}=8.314 \mathrm{J}{ \mathrm{mol}}^{-1}{ \mathrm{K}}^{-1}$

The voltage of the cell, $\mathrm{Pb}\left(\mathrm{s}\right) \left| {\mathrm{PbSO}}_4\left(\mathrm{s}\right) \right| {\mathrm{NaHSO}}_4 \left(0.6\mathrm{M}\right) \left|\right| {\mathrm{Pb}}^{2+} \left(2.5\times {10}^{-5}\right) | \mathrm{Pb}\left(\mathrm{s}\right)$ $\text{is} 0.061 \mathrm{V}. \text{Calculate }{\mathrm{K}}_2=\frac{\left[{\mathrm{H}}^{+}\right] \left[{\mathrm{SO}}_4^{2-}\right]}{\left[{\mathrm{HSO}}_4^{-}\right]}.$ If ${\mathrm{K}}_2 =\mathrm{a}\times {10}^{-2}$, report $\text{'}\mathrm{a}\text{'}$ correct up to one place of decimal.

$\text{Given,} {\mathrm{PbSO}}_4\left(\mathrm{s}\right)+2{\mathrm{e}}^{-}\to \mathrm{Pb}\left(\mathrm{s}\right)+{\mathrm{SO}}_4^{2-}\left(\mathrm{aq}\right); {\mathrm{E}}^0=-0.356 \mathrm{V}$ and ${\mathrm{Pb}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}\to \mathrm{Pb}\left(\mathrm{s}\right); {\mathrm{E}}^0=-0.126 \mathrm{V}$.