Which of the following strictly contains the minimum number of molecules?

Question

Professor PC Thomas Classes · Answer

(d) : The number of molecules is directly proportional to the number of moles ($n = 	ext{Mass} / 	ext{Molar mass}$). Moles of $\mathrm{N}_2 = 14/28 = 0.5 \mathrm{~mol}$. Moles of $\mathrm{H}_2 = 2/2 = 1.0 \mathrm{~mol}$. Moles of $\mathrm{NO}_2 = 46/46 = 1.0 \mathrm{~mol}$. Moles of $\mathrm{O}_2 = 8/32 = 0.25 \mathrm{~mol}$. Since $8 \mathrm{~g}$ of $\mathrm{O}_2$ represents the minimum number of moles ($0.25 \mathrm{~mol}$), it contains the minimum number of molecules.