CBSE 2023 · Region 2 · Set 1 · Q35 · 5 marks

(a)

Conductivity of $\displaystyle 2 \times 10^{-3} \mathrm{M}$ methanoic acid is $\displaystyle 8 \times 10^{-5} \mathrm{~S} \mathrm{~cm}^{-1}$. Calculate its molar conductivity and degree of dissociation if $\displaystyle \mathbf{\Lambda}_{\mathrm{m}}^{\mathrm{o}}$ for methanoic acid is $\displaystyle 404 \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1}$. $\displaystyle 3$ + $\displaystyle 2$

(b)

Calculate the $\displaystyle \Delta_{\mathrm{r}} \mathrm{G}^{\circ}$ and $\displaystyle \log \mathrm{K}_{\mathrm{c}}$ for the given reaction at $\displaystyle 298$ K: \[\mathrm{Ni}_{(\mathrm{s})}+2 \mathrm{Ag}_{(\mathrm{aq})}^{+} \rightleftharpoons \mathrm{Ni}^{2+}{ }_{(\mathrm{aq})}+2 \mathrm{Ag}_{(\mathrm{s})} \] Given: $\displaystyle \mathrm{E}^{\circ}{ }_{\mathrm{N}_{\mathrm{i}}}{ }^{2+} / \mathrm{N}_{\mathrm{i}}=-0.25 \mathrm{~V}, \mathrm{E}_{\mathrm{Ag}^{+} / \mathrm{Ag}}^{\mathrm{o}}=+0.80 \mathrm{~V}$ \[1 \mathrm{~F}=96500 \mathrm{C} \mathrm{~mol}^{-1} . \]

CBSE Class 12 Chemistry past-paper question from the 2023board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.