Question

Aniline, consists of carbon, hydrogen, and nitrogen. Combustion of this yields CO2, H20, and N2 as products. If the combustion of 12.5 g of aniline yields 7.1 grams of H2O, and 1.48 grams of N2, what is its empirical formula? [HINT: write out a chemical equation, consider law of conservation of mass, and then think about what percent hydrogen is in water]

A. CHN
B. C2H4N8
C. C16H15N2
D. C20H15N31

Answer 1

The empirical formula : C. C₁₆H₁₅N₂

Further explanation

Given

12.5 g of aniline

7.1 grams of H2O

1.48 grams of N2

Required

The empirical formula

Solution

Reaction :

mass H in H₂O :

= 2.1/18 x 7.1 g

= 0.79

mass N = 1.48

mass C :

= 12.5 g-(mass H+mass N)

= 12.5 - (0.79+1.48)

= 10.23

Mol ratio C : H : N =

= 10.23/12 : 0.79/1 : 1.48/14

= 0.853 : 0.79 : 0.106

= 8 : 7.5 : 1

= 16 : 15 : 2