Hello aspirant,

First we have to calculate the molar mass of organic compound having an empirical formula, CHBr

using ideal gas equation:

PV=nRT

where,

P = pressure of gas = 752 mm Hg = 0.989 atm

conversion used : (1 atm = 760 mmHg)

V = volume of gas = 24.2cm^3=24.2ml=0.0242L24.2cm3=24.2ml=0.0242L

conversion used :

(1cm^3=1ml)

(1L=1000ml)

(1cm3=1ml)

(1L=1000ml)

T = temperature of gas = 14^oC=273+14=287K14oC=273+14=287K

R = gas constant = 0.0821 L.atm/mol.K

w = mass of an organic compound = 0.188 g

M = molar mass of an organic compound = ?

Now put all the given values in the ideal gas equation, we get:

(0.989atm) * (0.0242L)=[{0.188g}/{M}] * (0.0821L.atm/mol.K)* (287K)

M=185.08g/mole

The Empirical formula = C H Br

The empirical formula weight = 12 + 1 + 80 = 93 gram/eq

Now we have to calculate the valency factor.

Formula used :

n= {Molecular formula}/{Empirical formula weight}}= {185.08}/{93}=1.99≈2

Molecular formula = (C H Br)n=(C H Br)2=C2H2Br2

Therefore, the molecular of the compound is, C2H2Br2.

Hope, this helps you.