JEE Main 2022 · 25 Jun · Shift 2 · Chemistry Q72

ChemistrySingle correct+4 / -1Question 72 of 90

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: Polluted water may have a value of BOD of the order of 17 ppm.

Reason R: BOD is a measure of oxygen required to oxidise both the bio-degradable and non-biodegradable organic material in water.

In the light of the above statements, choose the most appropriate answer from the options given below.

Both A and R are correct and R is the correct explanation of A.

Both A and R are correct but R is NOT the correct explanation of A.

A is correct but R is not correct.

A is not correct but R is correct.

Answer and worked solution

Official answer: C

Assertion is correct: clean water has BOD below about 5 ppm, while polluted water can reach 17 ppm or more.

Reason is wrong: BOD measures the oxygen used by microbes to break down biodegradable matter only.

(C)

Topics:Water and soil pollution

JEE Main 2022 · 25 Jun · Shift 2, Chemistry question 72