InterviewSolution
Saved Bookmarks
| 1. |
A hydrocarbon contains `10.5 g` of carbon per gram of hydrogen. `1 L` of vapour of the hydrocarbon at `127^(@)C` and 1 atm pressure weighs `2.8 g`. Find the molecular formula of the hydrocarbon.A. `C_(6)H_(14)`B. `C_(5)H_(10)`C. `C_(6)H_(12)`D. `C_(7)H_(8)` |
|
Answer» Correct Answer - D Using the general gas equation `: pV = nRT`, we have `1xx 1 = (2.8)/m xx 0.0821 xx 400 ` Hence, molar mmass `= 91.95` Atomic ratio `H = 1/1, C= 10.5/12 = 0.875 ` Lest whole number ratios: H = 8 and C = 7 (`0. 875` multiplied by 8 gives 7 as whole figure) Hence, empirical formula `= C_(7)H_(8)` Empirical formula weight = 92 Molar mass and empirical formula mass being the same, the molecular formula is `C_(7) H_(8) |
|