b
\(\mathrm{C}_{\mathrm{n}} \mathrm{H}_{2 \mathrm{an} 2}+\frac{3 \mathrm{n}+1}{2} \mathrm{O}_2 \longrightarrow \mathrm{nCO}_2+(\mathrm{n}+1) \mathrm{H}_2 \mathrm{O}\)

\(\underset{4 \mathrm{gm}}{\mathrm{CH}_4+2 \mathrm{O}_2} \longrightarrow \underset{11 \mathrm{gm}}{\mathrm{CO}_2+2 \mathrm{H}_2 \mathrm{O}}\)

\(0.25 \text { mole } \quad 0.25 \text { mole }\)

\(\left.0.25 \text { mole } \mathrm{CH}_4 \text { gives } 0.25 \text { mole (or } 11 \mathrm{gm}\right) \mathrm{CO}_2\)