Question

$2.0$ g of a metal oxide on strong heating gave $112$ ml of $O_2$ gas at STP. The equivalent weight of the metal is:

• A. $112$
• B. $56$
• C. $50$
• D. $92$

Answer 1

The correct option is D $92$

Equivalent mass $=\frac{\text{Weight of the metal}}{\text{Weight of oxygen}}\times 8$

Moles of $O_2$ liberated at STP = $\frac{112}{22400}=0.005moles.$

Therefore, weight of $O_2$ $=0.005\times 32=0.16g$

Weight of the metal $=$ Weight of metal oxide - Weight of oxygen$=$ $2-0.16$ $=$ $1.84$.

Equivalent weight $=$ $\frac{1.84}{0.16}$ x $8$ $=$ $92$.

Hence, option D is correct.