JEE Main 2022 · 29 Jun · Shift 2 · Chemistry Q84

ChemistryInteger+4 / -1Question 84 of 90

The cell potential for the given cell at 298 K

$\mathrm{Pt\,|\,H_2(g,1\,bar)\,|\,H^+(aq)\,||\,Cu^{2+}(aq)\,|\,Cu(s)}$

is 0.31V. The pH of the acidic solution is found to be 3, whereas the concentration of $\mathrm{Cu^{2+}}$ is $10^{-x}$ M. The value of $x$ is ______.

(Given: $E^\ominus_{\mathrm{Cu^{2+}/Cu}}=0.34$ V and $\dfrac{2.303RT}F=0.06$ V)

Your answer

Answer and worked solution

Official answer: 7

Nernst. $0.31=0.34-0.03\log\dfrac{[\mathrm{H^+}]^2}{[\mathrm{Cu^{2+}}]}=0.34-0.03(x-6)$ , so $x=7$ .

Answer: 7

JEE Main 2022 · 29 Jun · Shift 2, Chemistry question 84