Potassium chromate is isomorphous to potassium sulphate $\left(K_2{SO}_4\right)$. It is found to contain $26.78\%$ chromium. Calculate the atomic mass of chromium(At.wt $K=39.1$ )

Molecular formula of potassium chromate is $K_2{CrO}_4$

Let the weight of $Cr$ be a

So, $K_2{CrO}_4=39.1\times 2+a+16\times 4=142.2+a$.

Percentage of Cr in $K_2{CrO}_4=\frac{a}{142.2+a}\times 100$.

Percentage of Cr is = 26.78.

$\therefore \frac{100a}{142.2+a}=26.78$

a=52.0.

Therefore, option B is correct.