JEE Main 2025 — Electrochemistry Question with Solution

Consider the following half cell reaction

$${\text{Cr}}_2{\text{O}}_7^{2-}(\text{aq})+6{\text{e}}^{-}+14{\text{H}}^{+}(\text{aq})\to 2{\text{Cr}}^{3+}(\text{aq})+7{\text{H}}_2\text{O}(\ell )$$

The reaction was conducted with the ratio of $$\frac{[{\text{Cr}}^{3+}{]}^2}{[{\text{Cr}}_2{\text{O}}_7^{2-}]}=10^{-6}$$. The pH value at which the EMF of the half cell will become zero is __________.

(nearest integer value)

[Given: standard half cell reduction potential $$E_{{\text{Cr}}_2{\text{O}}_7^{2-},{\text{H}}^{+}/{\text{Cr}}^{3+}}^{\circ }=1.33\text{V}$$, $$\frac{2.303RT}{F}=0.059\text{V}$$.]