Question

An Organic compound contains 12.8% carbon ,2.1% hydrogen and 85.1% bromine , by mass . its relative molecular mass is 188 .a) calculate empirical formula b) Deduce its molecular formula

Answer 1

Answer:

Divide the percentages with atomic masses-

carbon

12

12.8

1.06 1

Hydrogen

1

2.1

2.1 2

Bromine

79.9

85.1

1.06 1

Empirical formula- CH

2

Br

(Empirical formula wt)

n

=188 or (94)

n

=188 or n=2

So molecular formula will be - (CH

2

Br)

2

=C

2

H

4

Br

2