10. Victor Meyer's Method for Molecular Weight

In this method small amount of weighed volatile liquid is converted into vapour. This vapour is collected and its volume is converted into STP or NTP. Now the weight of same volume of hydrogen at STP is calculated. Finally vapour density is calculated as:

After calculating V.D., molecular weight is calculated as:-

Molecular Weight = 2×Vapour Density.

Observation and Calculation, 

Wt. of Liquid = W₁ gm

Volume of vapour = V₁ ml

Pressure of vapour = (P₁) = p - f 

Room Temperature = T₁

At STP, 

Pressure (P₂) = 760mmHg

Temperature (T₂) = 273 K

Volume (V₂) = ?

We Know; 

Now, Molecular Weight = 2×VD = 2A.