For the given cell :

Cu(s) | Cu²⁺(C₁M) || Cu²⁺(C₂M) | Cu(s)

change in Gibbs energy ($\Delta$G) is negative, if :

Given $\Delta$G &lt; 0 <br><br>$\therefore$ -nFE_cell &lt; 0 <br><br>$\Rightarrow$ E_cell &gt; 0 <br><br>We know, E_cell = $E_{cell}^0$ - ${{RT} \over {2F}}\ln \left( {{{{C_1}} \over {{C_2}}}} \right)$ <br><br> = 0 - ${{RT} \over {2F}}\ln \left( {{{{C_1}} \over {{C_2}}}} \right)$ <br><br>$\therefore$ - ${{RT} \over {2F}}\ln \left( {{{{C_1}} \over {{C_2}}}} \right)$ &gt; 0 <br><br>$\Rightarrow$ $\ln \left( {{{{C_1}} \over {{C_2}}}} \right)$ &lt; 0 <br><br>$\Rightarrow$ C₁ &lt; C₂ <br><br>By checking option, we can see <br><br>C₂ = $\sqrt 2$C₁ satisfy the condition C₁ &lt; C₂.