Question

Assertion :The major pollutants in big and industralised cities are carbon monoxide and oxides of sulphur. Reason: CO is inhibitor of cytochrome oxidase.

• A. A and R both are true and R is correct explanation of A.
• B. A and R both are true but R is not correct explanation of A.
• C. A is correct and R is wrong.
• D. A is wrong and R is true.

Answer 1

The correct option is A A and R both are true and R is correct explanation of A.

The most important sources of $S{O}_2$ are fossil fuel combustion, smelting, manufacture of sulphuric acid, conversion of wood pulp to paper, incineration of refuse and production of elemental sulphur. Coal burning is the single largest man-made source of $S{O}_2$ accounting for about 50% of annual global emissions, with oil burning accounting for a further 25 - 30%. The major source of atmospheric CO is the spark ignition combustion engine. Smaller contributions come from processes involving the combustion of organic matter, for example in power stations and waste incineration. Carbon monoxide is toxic for mitochondria in man, altering the mitochondrial respiratory chain at the cytochrome c oxidase level. This inhibition in cytochrome c oxidase plays a role in the development of the symptoms observed in acute CO poisoning.