KVPY SX SB Exam 19-Nov-2017 Question Paper

The following reaction takes place at 298 K in an electrochemical cell involving two metals A and B,
${\mathit{A}}^{2+}\left(\mathit{a}\mathit{q}.\right)+\mathit{B}\left(\mathit{s}\right)\to {\mathit{B}}^{2+}\left(\mathit{a}\mathit{q}.\right)+\mathit{A}\left(\mathit{s}\right)$
With $\left[{\mathit{A}}^{2+}\right]=4\times {10}^{\mathit{–}3}$ M and $\left[{\mathit{B}}^{2+}\right]=2\times {10}^{\mathit{–}3}$M in the respective half-cells, the cell EMF is 1.091 V. The equilibrium constant of the reaction is closest to