Question

The figure shows how the emission of pollutants is related to the air/fuel ratio in an internal combustion engine using octane $C_8H_{18}$ (gasoline). Select the correct statement(s).

• A. Excess air leads to high $NO\left(g\right)$ levels
• B. Unburnt and partially burnt hydrocarbons lead to high $RH$ and $CO$ level
• C. Stoichiometric ratio of air to fuel (on a mass basis) is about 14.5 : 1 if air contains $24\% O_2$
• D. All of the above

Answer 1

Answer: (D)

As from figure, $NO\left(g\right)$ content is high when air content is high - correct.
(b) When gasoline is unburnt or partially burnt, it means air to fuel ratio is not stoichiometrically, hence content of $CO$ and $C_8H_{18}$ is high—correct

$\frac{400}{0.24}g$ air $=1667g$
Ratio of air to fuel $=14:6:1$