Question

A quantity of $8.6g$ of an oxide of a metal reacts completely with hydrogen gas to yield $1.8g$ of water. The equivalent weight of the metal is:

• A. 23
• B. 27
• C. 32.5
• D. 35

Answer 1

The correct option is D 35

$MO+H_2\to H_{2}O+M$

8.6 g 1.8 g

$\frac{no.ofmolesofMO}{itscoefficient}=\frac{no.ofmolesof{H}_{2}O}{itscoefficient}$

$\frac{\left(8.6/M\right)}{1}=\frac{\left(1.8/18\right)}{1}$

$M=\frac{8.6\times 18}{1.8}=86$

M = molecular mass of MO

now let molecular mass of M (metal)

is x

then $MO=x+16$

$\Rightarrow x+16=86$

$x=70$

its equivalent weight = $\frac{70}{2}=35$