Q60 / 180 · AIIMS 2005 · Chemistry
The chemical reaction,
$$
2 \mathrm{AgCl}_{(s)}+\mathrm{H}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{HCl}_{(a q)}+2 \mathrm{Ag}_{(s)}
$$
taking place in a galvanic cell is represented by the notation
- A$\mathrm{Pt}_{(s)} \mid \mathrm{H}_{2(g),}, 1$ bar $\left|1 \mathrm{M} \mathrm{KCl}_{(a q)}\right| \mathrm{AgCl}_{(s)} \mid \mathrm{Ag}_{(s)}$
- Correct answerB$\mathrm{Pt}_{(s)} \mid \mathrm{H}_{2(\mathrm{~g})}, 1$ bar $\left|1 \mathrm{MHCl}_{(a q)}\right| 1 \mathrm{M} \mathrm{Ag}_{(a q)} \mid \mathrm{Ag}_{(s)}$
- C$\mathrm{Pt}_{(s)} \mid \mathrm{H}_{2(g),}, 1$ bar $\left|1 \mathrm{MHCl}_{(a q)}\right| \mathrm{AgCl}_{(s)} \mid \mathrm{Ag}_{(s)}$
- D$\mathrm{Pt}_{(s)} \mid \mathrm{H}_{2(g),}, 1$ bar $\left|1 \mathrm{MHCl}_{(a q)}\right| \mathrm{Ag}_{(s)} \mid \mathrm{AgCl}_{(s)}$
Solution
$2 \mathrm{AgCl}_{(s)}+\mathrm{H}_{2(g)} \rightarrow 2 \mathrm{HCl}_{(a q)}+2 \mathrm{Ag}_{(s)}$ The activities of solids and liquids are taken as unity and at low concentrations, the activity of a solute is approximated to its molarity.
The cell reaction will be
$$
\mathrm{Pt}_{(s)} \mid \mathrm{H}_{2(\mathrm{~g})}, 1 \text { bar }\left|\mathrm{H}_{(a q)}^{+} 1 \mathrm{M} \| \mathrm{AgCl}_{(a q)} 1 \mathrm{M}\right| \mathrm{Ag}_{(s)}
$$
Hence, the correct answer is option: 'B'.