Question

A compound which is having hydrogen and carbon is called hydrocarbon. A hydrocarbon is heated in an excess of oxygen to produce $58.67$ g of $C{O}_2$ and $27$ g of $H_{2}O$. What is the empirical formula of the hydrocarbon?

• A. $C_3{H}_9$
• B. $C_4{H}_{12}$
• C. $C_8{H}_{18}$
• D. $C_4{H}_9$

Answer 1

The correct option is D $C_4{H}_9$

Let the empirical formula of the hydrocarbon be $C_x{H}_y$.
$C_x{H}_y+z{O}_2⟶xC{O}_2+\frac{y}{2}{H}_{2}O$
The mass of $C{O}_2$ is 58.67 g.
The mass of $H_{2}O$ is = 27 g.
The mass of carbon in $C{O}_2=\frac{58.67\times 12}{44}=16$ g.
The mass of hydrogen in $H_{2}O=\frac{27\times 2}{18}=3$ g.
The number of moles of C in compound $=\frac{16}{12}=1.33$.
The number of moles of H in compound $=\frac{3}{1}=3$.
The ratio of the number of moles of C to the number of moles of H in the compound $=\frac{1.33}{3}=\frac{4}{9}$.
The empirical formula of the hydrocarbon will be $C_3{H}_9$.