At 298 K, a 1 litre solution containing 10m mol of Cr₂O₇^2- and 100m mol Cr³⁺ shows a pH of 3.0.
Given: Cr₂O₇²⁺ → Cr³⁺; E⁰ = 1.330V and $\frac{2.303\mathrm{RT}}{\mathrm{F}}$ = 0.059 V
The potential for the half cell reaction is $\mathrm{x}\times {10}^{-3}\mathrm{V}$. The value of x  is___