Some Basic Concepts Of Chemistry Question 149
Question: 1 mol of a gaseous aliphahatic compound $ C _{n}H _{3n}O _{m} $ is completely burnt in an excess of oxygen. The contraction in volume is (assume water get condensed out)
Options:
A) $ ( 1+\frac{1}{2}n-\frac{3}{4}m ) $
B) $ ( 1+\frac{3}{4}n-\frac{1}{4}m ) $
C) $ ( 1-\frac{1}{2}n-\frac{3}{4}m ) $
D) $ ( 1+\frac{3}{4}n-\frac{1}{2}m ) $
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Answer:
Correct Answer: D
Solution:
[d] $ C _{n}H _{3n}O _{m}+yO _2\xrightarrow[{}]{{}}nCo _2(g)+\frac{3n}{2}H _2O(l) $ Contraction in volume= Contraction in moles of gas $ =1\frac{3n}{4}-\frac{m}{2} $
$ =1+\frac{3n}{4}-\frac{m}{2} $
$ \Rightarrow $ $ ( 2n+\frac{3n}{2}-m )\times \frac{1}{2}=y $
$ \Rightarrow $ $ n+\frac{3n}{4}-\frac{m}{2}=y $
