Question

Potassium selenate contains $50.0$% $Se$ and is isomorphous with potassium sulphate. Assume the atomic weight of $Se$ is $71\times X$. Find the value of $X$.

Answer 1

We have,

Potassium selenate = $K_{2}Se{O}_4$

So, molecular weight $=2\times 39+x+4\times 16$

Since it contains $50$% $Se$

So, mass of Se $=x=2\times 39+4\times 16=142$

So, the atomic mass of Se $=142=71\times X$

So, we get $X=2$