Question

Assertion: Detergents with a straight chain of hydrocarbons are preferred over a branch chain.
Reason: Detergents with branched chain hydrocarbon parts are expensive.
A) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion
C) Assertion is correct and Reason is incorrect
D) Both Assertion and Reason are incorrect

Answer 1

Hint: Detergents are salt of sulfonic acid or alkyl hydrogen sulphate. Detergents are classified into two main groups depending on the types of hydrocarbons present in it. The two main types of detergents are biodegradable and non-biodegradable detergents.

Complete step-by-step answer:
We use detergents regularly in our house for cleaning purposes. Detergents act as cleansing agents. Detergents have wonderful dirt dissolution properties. They lower the surface tension of water and act as a cleansing agent like soap.Depending on the active part on the surface of the molecule synthetic detergents are classified as cationic detergents, anionic detergents and non-ionic detergents.

Based on degradable properties, detergents are also classified into biodegradable and non-biodegradable detergents. From the name, we can say that biodegradable detergents are detergents that can be degraded by bacteria. Biodegradable detergents contain straight chain hydrocarbons so they can be degraded by bacteria. Eg. Sodium alkyl benzene sulphonate

Non-biodegradable detergents are detergents that cannot be degraded by bacteria. Non-biodegradable detergents contain branch hydrocarbons so they cannot be degraded by bacteria. These detergents discharge into water and cause serious pollution problems. Eg. Cetyl methyl ammonium bromide.

Hence we can say that the given Assertion “Detergents with a straight chain of hydrocarbons are preferred over a branch chain” is correct.

But the given reason that “Detergents with branched chain hydrocarbon parts are expensive “is incorrect. Detergents with a straight chain of hydrocarbons are preferred over a branch chain as they are biodegradable.

Hence, the correct option is (C) Assertion is correct and Reason is incorrect

Note: Nowadays detergents are more preferable than soap. As detergents are effective in hard water as well. Due to the presence of minerals of calcium and magnesium ion soap less effective in hard water. So biodegradable detergents containing straight chain hydrocarbons are more popular.