A bag contains `0.32 g` of oxygen. The same valume of an unknown gas `A` under similar conditions of temperature and pressure weigh `0.26 g`. The gas `A` is known to contain only `C` and `H` in 1:1 ratio. The molecular formula of the compound is

Options

A. `C_(2)H_(2)`
B. `C_(4)H_(4)`
C. `C_(3)H_(4)`
D. `CH`

Answer

A

Explanation

Moles of `O_(2)` in bag `A = 0.32//32 = 0.01` mol
Same volume of unknown gas = 0.01 mol
0.01 mol of unknown gas `A = 0.26 g`
mol of unknown `A = (0.26)/(0.01) = 26 g`
`Mw` of unknown gas `A = 26 g`
Empirical formula `= CH`
Empirical formula weight `= 12 + 1 = 13g`
`n = ("Molecular formula weight")/("Empirical formula weight") = (26)/(13) = 2`
Molecular formula `= (CH)_(2) = C_(2) H_(2)`.