Question

At identical temperature and pressure, the rate of diffusion of hydrogen gas is 3 times that of a hydrocarbon having molecular formula cnh2n2. What is the value of n ?

Answer 1

Answer ⇒ n = 1.

It is given confusing in question about mol. formula. As what I thinks, It should be, $C_nH_2_n_+_2$

Explanation ⇒ By the Graham's Law of diffusion, the rate of diffusion of any gas is inversely proportional to the square root of Molar mass of that gas.

Let Molar mass of Hydrocarbon be M and that of Hydrogen be m.

Let rate of diffusion of Hydrocarbon be R and that of Hydrogen be r.

Then,   R/r = √(m/M)

It is given, rate of diffusion of Hydrogen = 3 × rate of diffusion of Hydrocarbon.

∴ r = 3R

Putting this in Graham's equation, we get,

R/3R = √(m/M)

∴ 1/9 = m/M

∴ M = 9m

∴ M = 9 × 2 [Molar mass of Hydrogen = m = 2 g/mole.]

∴ M = 18 g/mole.

Now, Molar mass of hydrocarbon = 12n + (2n + 2)1

= 12n + 2n + 2

= 14n + 2

∴ 14n + 2 = 18

∴ n = 16/14

∴ n = 8/7

∴ n ≈ 1

∴ $C_nH_2_n_+_2 = CH_4$

Hope it helps.

Answer 2

Answer:

4

Explanation:

Hope it will help u.........Mark as brainliest