• # question_answer 3) A compound contains 4.07% hydrogen, 24.27% carbon and 71.65% chlorine. Its molecular mass is 98.96. What are its empirical and molecular formula?

Element % Atomic mass Relative no. of atoms Simplest ratio Whole no. ratio Carbon 24.27 12 $\frac{24.27}{12}=2.022$ $\frac{2.022}{2.018}\approx 1$ 1 Hydrogen 4.07 1 $\frac{4.07}{1}=4.07$ $\frac{4.07}{2.018}\approx 2$ 2 Chlorine 71.65 35.5 $\frac{71.65}{355}=2018$ $\frac{2.018}{2.018}=1$ 1   Empirical formula = $C{{H}_{2}}Cl$ Molecular formula = ${{\left( C{{H}_{2}}Cl \right)}_{n}}$ $n=\frac{Molecular\text{ }mass}{Empirical\text{ }formula\text{ }mass~}=\frac{98.96}{49.5}\approx 2$ $\therefore$Molecular formula = ${{(C{{H}_{2}}Cl)}_{2}}={{C}_{2}}{{H}_{4}}C{{l}_{2}}$