Question

Salts of metals $X,Y$ and $Z$ are electrolyzed under identical conditions using the same quantity of electricity. It was observed that $4.2$ g of $X$, $5.4$ g of $Y$ and $19.2$ g of $Z$ were deposited at the respective cathode. If the atomic weights of $X,Y,Z$ are $7,27$ and $64$ respectively, then their ratio valencies is :

• A. $1:2:3$
• B. $1:3:2$
• C. $2:3:1$
• D. $3:2:2$

Answer 1

Answer: (B)

$1:3:2$

Number of moles of X, Y and Z are $\frac{4.2}{7}:\frac{5.4}{27}:\frac{19.2}{64}$ are $0.6:0.2:0.3$

So, $6:2:3$ since same current is passed so there number of equivalence will be same.

So, using that concept gives the ratio's of valence $1:3:2$

Hence option $B$ is correct.