Question

A gaseous hydrocarbon on analysis gave the following data .
C=82.7%
H=17.3%
The mass of 132ml [measured at NTP] of it is 0.342g. Find the molecular formula of the hydrocarbon.

Answer 1

volume of one mole gas at NTP = 24L
132ml gives   ------------    0.342g
1ml gives ----------------   0.342/132 g
1L gives -----------------  342/132 g
24 L gives ----------------- 342*24/132 = 62.18g
mole of  carbon = 82.7 / 12 = 6.89
mole of hydrogen = 17.3/1 = 17.3
relative number of atom of each atom :
for C = 6.89/6.89 = 1
for H = 17.3/6.89 = 2.5
empirical formula = C2H5 
empirical formula mass = 2*12 + 5*1 = 29
n*empirical formula mass = molecular formula mass
n*29 = 62.18 
n = 62.18/29 = 2.14 = 2    (we can assume it is equal to 2)
molecular formula = 2*(C2H5)
                           = C4H10 , butane

Answer 2

Answer:

Here is your answer

Explanation:

Emperical formula = C2H5

and n = 2 (approx)

So, Molecular formula = C4H10