If one mole of hydrocarbon contain 4g of hydrogen and it molar mass is 40g.what is the homologous series of the compound

Answer 1

%H = (4/40)*100 = 10%
%C = 100-10 = 90%.

Take 100 g sample which gives you
10g H and 90 g C.
mols C = 90/12 = about 7.5
mols H = 10/1 = about 10
Find the ratio of the elements to each other.
The easy way to do that is to divide both numbers by the smaller number.
C = 7.5/7.5 = 1.00
H = 10/7.5 = 1.33
To obtan whole numbers, multiply both by 3 to give C = 3 and H = 4
C3H4 is the molecular formula. Does that equal molar mass of 40? Yes (36+4=40).
The homologous series then is CnHn+1

Answer 2

Nice Work🤍