Question

plz help me out wid this.....with proper explanation.

Molecular weight of the alkane was found to be 142.Suggest its molecular formula.

Answer 1

see dear, for any alkane u know very well that formula wil be

$C_{n} H_{2n+2}$

at wt. of C=12 & H=1

so itz molecular mass will be

12*n+(2n+2)1 which must be equal to 142

so lets solve it

14n+2=142

n=142-2/14=10

Formula will be

$C_{10} H_{22}$