Question

Equal weights of $X$ (atomic weight $=36)$ and $Y$ (atomic weight $=24)$ are reacted to form the compound $X_2{Y}_3$. Which of the following is/are correct?

• A. $X$ is the limiting reagent.
• B. $Y$ is the limiting reagent.
• C. No reactant is left over.
• D. Mass of $X_2{Y}_3$ formed is double the mass of X taken.

Answer 1

Answer: (C), (D)

The correct options are
C Mass of $X_2{Y}_3$ formed is double the mass of X taken.
D No reactant is left over.

Let $a$ g of $X$ and also $Y$ be taken.
Given the following reaction:
$2X+3Y\to X_2{Y}_3$
$\Rightarrow \frac{a}{36}\frac{a}{24}$ (Initial moles)
$\Rightarrow --\frac{a}{72}$ (Final moles)
Since both $X$ and $Y$ are completely consumed, there is no limiting reagent.
Moles of $X_2{Y}_3=\frac{a}{72}$,
(Mw of $X_2{Y}_3=2\times 36+24\times 3=144$ g/mol).
Weight of $X_2{Y}_3=\frac{a}{72}\times 144=2a=2\times$ Weight of $X$.