Question

The function of an automobile catalytic converter is to control emissions of:
(A) Carbon dioxide and hydrogen
(B) Carbon monoxide and hydrocarbons
(C) Carbon monoxide and carbon dioxide
(D) Carbon monoxide and nitrogen dioxide

Answer 1

A catalytic converter is a device that uses a catalyst to convert three harmful compounds in car exhaust into harmless compounds like carbon dioxide and water. We all know that there is a large amount of release of pollutants in the form of unburned gasoline or from the combustion of gasoline by the automobile’s engine.

Complete step by step solution:
A catalytic converter is a simple device that works on basic redox reactions to reduce the pollutants that an automobile makes. It converts around 98 % of the harmful substances produced by a car engine into less harmful gases. In a catalytic converter, catalysts such as platinum and palladium are used. The catalyst is coated onto a ceramic honeycomb or ceramic beads that are housed in a muffler-like package attached to the exhaust pipe. The converter uses simple oxidation and reduction reactions to convert unwanted fumes and catalyst helps it in the process. The three harmful pollutants that the engine makes are-
-Hydrocarbons (in the form of unburned gasoline),
-Nitrogen oxides (created when the heat in the engine forces nitrogen in the air to combine with oxygen) and,
-Carbon monoxide (formed by the combustion of gasoline).
A three-way catalytic converter does the following three functions simultaneously:
1. Reduction of nitrogen oxides into elemental nitrogen and oxygen:
$N{O_x} \to {N_x} + {O_x}$
2. Oxidation of carbon monoxide to carbon dioxide:
$CO + {O_2} \to C{O_2}$
3. Oxidation of hydrocarbons into carbon dioxide and water:
${C_x}{H_{4x}} + 2x{O_2} \to xC{O_2} + 2x{H_2}O$
Option B contains carbon monoxide and hydrocarbons which are among the harmful pollutants and catalytic converters control their emissions by converting them into harmless carbon dioxide and water. Thus, option B is the correct answer.

Note: Hydrocarbons, carbon monoxide and nitrogen oxides are extremely harmful to our environment. Carbon monoxide is a poison for any air-breathing animal. Nitrogen oxides lead to smog, acid rain and hydrocarbons produce smog. Catalytic converters also have some detrimental environmental effects. In the conversion of hydrocarbons and carbon monoxide, carbon dioxide is produced which is a greenhouse gas and contributes significantly to global warming.