A given volume of methane diffuses in 20s. How long will it take the same volume of sulphur (IV) oxide to diffuse under the same conditions? [C = 12, H = 1, S = 32, O = 16

A. 5s
B. 20s
C. 40s
D. 60s

Correct Answer:

Option C – 40s

Explanation

Relative molecular mass of CH4 = 12 X 1 + 4 = 16
Relative molecular mass of SO2 = 32 + 10 X 2 = 64
tSO2/tCH4 = √MSO2/MCH4
t/20 = √64/16 = √4
t/20 = 2
∴ t = 20 X 2 = 40sec