Question

A mixture of $CO$ and $H_2$ was exploded with $31ml$ of $O_2$. The volume after the explosion was $29ml$, which reduced to $12ml$ when shaken with $KOH$. Find the percentage of $H_2$ in the mixture.

• A. $44.7\%$
• B. $60.1\%$
• C. $50\%$
• D. $55.3\%$

Answer 1

The correct option is D $55.3\%$

$CO+\frac{1}{2}{O}_2\to C{O}_2$

$xml$ $\frac{x}{2}ml$ $xml$

$H_2+\frac{1}{2}{O}_2\to H_{2}O$

$yml$ $\frac{y}{2}ml$ $yml$

$\because$ Volume contracted by $17ml$ when $KOH$ was mixed.

$\therefore$ Volume of $KOH=17=x$

$\therefore O_2$ left $=12ml$

$\therefore O_2$ consumed $=19ml$

$\therefore O_2$ consumed in 2nd $rxn=19-\frac{17}{2}=\frac{21}{2}ml$

$\therefore$ Volume of $H_2=21ml$

$\therefore H_2=\frac{21}{21+17}\times 100$

$=55.26$%