Q26 / 150 · MHT CET 2026 (18 April Shift 2) · Chemistry
Find the number of molecules present in 70 g dinitrogen.
- Correct answerA$1.5055 \times 10^{24}$
- B$1.5055 \times 10^{23}$
- C$3.011 \times 10^{24}$
- D$3.011 \times 10^{23}$
Solution
Molar mass of dinitrogen ($N_2$) is $28 \text{ g mol}^{-1}$
Number of moles of $N_2$ = $\dfrac{70}{28} = 2.5 \text{ mol}$
Number of molecules = $n \times N_A$
Number of molecules = $2.5 \times 6.022 \times 10^{23} = 1.5055 \times 10^{24}$
Answer: $1.5055 \times 10^{24}$
Number of moles of $N_2$ = $\dfrac{70}{28} = 2.5 \text{ mol}$
Number of molecules = $n \times N_A$
Number of molecules = $2.5 \times 6.022 \times 10^{23} = 1.5055 \times 10^{24}$
Answer: $1.5055 \times 10^{24}$
Hence, the correct answer is option: 'A'.