JEE Main & Advanced Chemistry Some Basic Concepts of Chemistry / रसायन की कुछ मूलभूत अवधारणाएँ Question Bank Self Evaluation Test - Some Basic Concepts of Chemistry

Complete combustion of \[0.858\text{ }g\] of compound X gives 2.64 g of \[C{{O}_{2}}\] and 1.26g of\[{{H}_{2}}O\]. The lowest molecular mass X can have:

A) 43 g

B) 86 g

C) 129 g

D) 172 g

Correct Answer: A

Solution :

[a]

Moles of \[C={}^{n}C{{O}_{2}}=\frac{2.64}{44}=0.06\] \[\Rightarrow \] mass of C= 0.72

Mole of \[H=2\times Moles\]of \[{{H}_{2}}O=\]\[2\times \frac{1.26}{18}=0.14\Rightarrow \]mass of \[H=0.14\]

Compound does not contains oxygen.

So \[EF\to {{C}_{0.06}}{{H}_{0.14}}\Rightarrow {{C}_{3}}{{H}_{17}}\] \[\Rightarrow \] Lowest M.M. = 43