Chemistry · Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry

NEET (UG) 2024 — Question 96

A compound $X$ contains $32 \%$ of $A, 20 \%$ of $B$ and remaining percentage of $C$ . Then, the empirical

formula of $X$ is : (Given atomic masses of $A=64 ; B=40 ; C=32 u$ )

Answer: B

Element	Mass percentage %	No. of moles	No. of moles/ Smallest number	Simplest whole number
A	$32\text{ }\!\!%\!\!\text{ }$	$\frac{32}{64}=\frac{1}{2}$	$\frac{1}{2}\times 2$	$=1$
B	$20\text{ }\!\!%\!\!\text{ }$	$\frac{20}{40}=\frac{1}{2}$	$\frac{1}{2}\times 2$	$=1$
C	$48\text{ }\!\!%\!\!\text{ }$	$\frac{48}{32}=\frac{3}{2}$	$\frac{3}{2}\times 2$	$=3$

So, empirical formula of $X=\begin{array}{lllll}A & : & B & : & C 1 & : & 1 & : & 3\end{array}$

$\therefore$ The correct empirical formula of compound X is $\mathrm{ABC}_{3}$

Answer key and solution verified before publishing.

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