Question

The empirical formula of an organic compound containing carbon and hydrogen is $CH_2$. The mass of one litre of this organic gas is exactly equal to that of one litre of $N_2$. Therefore, the molecular formula of the organic gas is

• A. $C_2H_4$
• B. $C_3H_6$
• C. $C_6H_{12}$
• D. $C_4H_8$

Answer 1

Answer: (A)

$C_2H_4$

Answer 2

Mass of 1 L of gas = mass of 1 L of $N_2$ according to Avogadro?? hypothesis. Molecular masses will also be equal, then molecular mass of the $gas = 28$. Hence formula is $C_2H_4 (2 ? 12 + 4 ? 1 = 28)$.