Which of the following gases is/are lighter than air? 1. Hydrogen chloride 2. Sulfur dioxide 3. Helium Select the correct answer using the code given below.

উত্তর দেখান ও ব্যাখ্যা

উত্তর: (A) Only 3

ব্যাখ্যা

Air's average molar mass is about 29 g/mol. Helium (4) is lighter; HCl (36.5) and SO2 (64) are heavier.