Some Basic Concepts Of Chemistry Question 47
Question: Complete combustion of $ 0.858g $ of compound X gives 2.64 g of $ CO _2 $ and 1.26g of $ H _2O $ . The lowest molecular mass X can have:
Options:
A) 43 g
B) 86 g
C) 129 g
D) 172 g
Show Answer
Answer:
Correct Answer: A
Solution:
[a]
Moles of $ C={}^{n}CO _2=\frac{2.64}{44}=0.06 $
$ \Rightarrow $ mass of C= 0.72
Mole of $ H=2\times Moles $ of $ H _2O= $ $ 2\times \frac{1.26}{18}=0.14\Rightarrow $ mass of $ H=0.14 $
Compound does not contains oxygen.
So $ EF\to {C _{0.06}}{H _{0.14}}\Rightarrow C _3H _{17} $
$ \Rightarrow $ Lowest M.M. = 43
