Answer:
CH₄
Explanation:
According to Graham's law, the rate of effusion of a gas (r) is inversely proportional to the square root of its molar mass (M).
Let's consider the following gases and their molar masses.
A) NH₃ 17.03 g/mol
B) CH₄ 16.04 g/mol
C) Ar 39.95 g/mol
D) HBr 80.91 g/mol
E) HCl 36.46 g/mol
Of these gases, CH₄ will have the greatest rate of effusion at a given temperature because it has the lowest molar mass.
