JEE Main 2023 — Chemistry Physical Chemistry

2023integerhard

At $298K$ , the standard reduction potential for ${\mathrm{Cu}}^{2+}/\mathrm{Cu}$ electrode is $0.34V$ . Given : ${K}_{\mathrm{sp}}\mathrm{Cu}(\mathrm{OH}{)}_{2}=1\times {10}^{-20}$ Take $\frac{2.303\mathrm{RT}}{F}=0.059V$ The reduction potential at $\mathrm{pH}=14$ for the above couple is $(-)x\times {10}^{-2}V$ . The value of x is

Official previous-year question

Held on 13 Apr 2023 · Verified 6 Jul 2026.

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Solution

For the reaction:

${\mathrm{Cu}}^{2+}(\mathrm{aq})+2{e}^{-}\rightarrow \mathrm{Cu}(s)$

The reduction potential is

$E={E}^{ο}-\frac{\mathrm{RT}}{2F}\mathrm{ln}\frac{1}{[{\mathrm{Cu}}^{2+}]}$

From the given data $\mathrm{pH}=14$ and

${K}_{\mathrm{sp}}=(\mathrm{Cu}{(\mathrm{OH})}_{2})=1.0\times {10}^{-20}$ , we get

$[{H}^{+}]={10}^{-14}M,[{\mathrm{OH}}^{-}]=\frac{{K}_{W}}{[{H}^{+}]}=\frac{{10}^{-14}{M}^{2}}{{10}^{-14}M}=1M$

$[{\mathrm{Cu}}^{2+}]=\frac{{K}_{\mathrm{sp}}}{{[{\mathrm{OH}}^{-}]}^{2}}=\frac{1.0\times {10}^{-20}{M}^{2}}{1M}=1.0\times {10}^{-20}M$

$E=0.34V-(\frac{0.059V}{2})\mathrm{log}\frac{1}{1.0\times {10}^{-20}}=0.34V-\frac{0.059\times 20V}{2} E=0.34-0.59=-0.25V$

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JEE Main 2023 — Chemistry Physical Chemistry

2023integerhard

Official previous-year question

Held on 13 Apr 2023 · Verified 6 Jul 2026.

Did you get this right?

Solution

For the reaction:

${\mathrm{Cu}}^{2+}(\mathrm{aq})+2{e}^{-}\rightarrow \mathrm{Cu}(s)$

The reduction potential is

$E={E}^{ο}-\frac{\mathrm{RT}}{2F}\mathrm{ln}\frac{1}{[{\mathrm{Cu}}^{2+}]}$

From the given data $\mathrm{pH}=14$ and

${K}_{\mathrm{sp}}=(\mathrm{Cu}{(\mathrm{OH})}_{2})=1.0\times {10}^{-20}$ , we get

$[{H}^{+}]={10}^{-14}M,[{\mathrm{OH}}^{-}]=\frac{{K}_{W}}{[{H}^{+}]}=\frac{{10}^{-14}{M}^{2}}{{10}^{-14}M}=1M$

$[{\mathrm{Cu}}^{2+}]=\frac{{K}_{\mathrm{sp}}}{{[{\mathrm{OH}}^{-}]}^{2}}=\frac{1.0\times {10}^{-20}{M}^{2}}{1M}=1.0\times {10}^{-20}M$

$E=0.34V-(\frac{0.059V}{2})\mathrm{log}\frac{1}{1.0\times {10}^{-20}}=0.34V-\frac{0.059\times 20V}{2} E=0.34-0.59=-0.25V$

JEE Main 2023 — Chemistry Physical Chemistry

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JEE Main 2023 — Chemistry Physical Chemistry

Did you get this right?

Solution

Your note

JEE Main Physical Chemistry in other years

More JEE Main Physical Chemistry questions

Other Chemistry topics for JEE Main

Organic Chemistry

Inorganic Chemistry

Keep practicing Physical Chemistry