Question

A metal oxide contains $70\%$ metal with molar mass of metal is $56$. And the molar mass of compound is $160$.its Molecular formula will be:

• A. $M_2{O}_3$
• B. $M_2{O}_5$
• C. $MO$
• D. $M{O}_2$

Answer 1

Answer: (A)

$M_2{O}_3$

Let $n$ be the number of oxygen per $1$ atom of metal.

Atomic weight $M=56$

In oxide , metal is $70\%$ by mass

oxygen is $30\%$ by mass

Let the proportional of the m,ass of metal and oxygen.

$56:n\times 16=70:30$

$16n=\frac{56\times 30}{70}$

$n=1.5$

Hence there are two atoms of metal and three atoms of oxygen

$M_2{O}_3$