Question

a hydrocarbon contains 10.5 gm of carbon per 1 gm of hydrogen. At 127°C temperature and 1 atm pressure, the vapour weight of the hydrocarbon is 2.8 gm. Determine the molecular formula of the compound​

Answer 1

ANSWER

As we know,

PV=nRT=wM/RT

or 1= 2.8/M ×0.0821×400

or M=91.95≈92

Let the formula be C a H b

.

So 12a+b=92b

12a

=10.5(given)

11.5b=92

or b=8

∴ a=7

Therefore, the formula is C

7

H

8

.

molar mass = 12*7+1*8 = 92gm/mole