Question

A certain amount of metal, whose equivalent mass is $28$, displaces $0.7\, L$ of $H_2$ at STP from an acid. Mass of the element is

• A. $1.75 \,g$
• B. $0.875\, g$
• C. $3.50 \,g$
• D. $7.00\, g$

Answer 1

Answer: (A)

$1.75 \,g$

Answer 2

Gram equivalent of metal $=$ Gram equivalent of $H _{2}$ $\frac{\text{Weight of metal}}{\text{Equivalent wt. of metal}} =$ moles of $H _{2} \times$ valency factor $\frac{\text { Weight }}{28}=\frac{\text { given volume }}{22.4} \times 2$ $\frac{\text { Weight }}{28}=\frac{0.7}{22.4} \times 2$ Weight $=1.75\, gm$