Which of the following substance contains 1.204 x 10

^{24} **atoms**?

A 1 mol of nitrogen gas

B 1 mol of ammonia

C 1 mol of water

D 1 mol of argon

Many of my students choose the wrong answer in the current topical test.

1 mol of nitrogen gas consists of 1 x 6.02 x 10

^{23} **molecules. **

Number of **atoms** in 1 mol of nitrogen gas is 2 x 6.02 x 10^{23} .
(Each nitrogen, N

_{2} molecule consists of 2 nitrogen atoms)

1 mol of ammonia consists of 1 x 6.02 x 10

^{23} **molecules**

Number of **atoms** in 1 mol of ammonia gas is 4 x 6.02 x 10^{23.}
(Each ammonia, NH

_{3} molecule consists of 4 atoms)

1 mol of water consists of 1 x 6.02 x 10

^{23} **molecules**

Number of **atoms** in 1 mol of water is 3 x 6.02 x 10^{23}
(Each water, H

2O molecule consists of 3 atoms)

1 mol of argon consistss of 1 x 6.02 x 10

^{23} **atoms. **

**The correct answer : A**