Question

Equal volume of two gases 'A & B diffuse through
a porous pot in 40 and 10 seconds respectively. If
the molar mass of 'R is 100, then calculate the
molar mass of gas 'B'.
(1) 10 g/mol
(2) 8.5 g/mol
(3) 6.25 g/mol (1) 4 g/mol
dhe​

Answer 1

Answer:

The molar mass of gas B is 6.25 g/mol.

Explanation:

Given data:

Volume of gas A & B are same i.e., VA = VB = V

Time taken by gas A to diffuse, tA = 40 s

Time taken by gas B to diffuse, tB = 10 s

The molar mass of gas A, mA = 100 g /mol

To find: the molar mass of gas B, mB

Let the rate of diffusion of gas A & B be “rA” & ”rB”

We know,

Rate of diffusion, r = V / t

Using Graham’s Law,

$\frac{rA}{rB}$ = $\sqrt{\frac{mB}{mA}}$

or, [V/tA] / [V/tB] = √ [mB/mA]

or, [V/40]² / [V/10]² = [mB/100]

or, 100 / 1600 = mB / 100

or, mB = 25 / 4 = 6.25 g/mol