Question

A mixture of gases contains $H_2$ and $O_2$ gases in the ratio of $1:4$ ($w/w$). What is the molar ratio of the two gases in the mixture?

• A. $16:1$
• B. $2:1$
• C. $1:4$
• D. $4:1$

Answer 1

The correct option is D $4:1$

A mixture of gases contains $H_2$ and $O_2$ gases in the ratio of $1:4$ (w/w).
Let $100$ g of hydrogen and $400$ g of oxygen are present.
The molar masses of hydrogen and oxygen are $2$ g/mol and $32$ g/mol respectively.
The number of moles of hydrogen present are $\frac{100}{2}=50$ mol.
The number of moles of oxygen present are $\frac{400}{32}=12.5$ mol.
The molar ratio of the two gases in the mixture is $50:12.5$ or $4:1$.