Question

A gas has molecular formula $(CH)_{n}$. If vapour density of the gas is 39, what should be the formula of the compound?

• A. $C_{3}H_{3}$
• B. $C_{4}H_{4}$
• C. $C_{2}H_{2}$
• D. $C_{6}H_{6}$

Answer 1

Answer: (D)

$C_{6}H_{6}$

Answer 2

(4) : Mol. Wt. $= 2 \times V.D. = 2 \times 39 = 78$

($(CH)_{n} = (13)_{n}or13 \times n = 78$)

$n = 78/13 = 6$

$\therefore$Molecular formula= $C_{6}H_{6}$