Q2 / 180 · KCET 2025 · Chemistry
The electronic configuration of X and Y are given below:
$\begin{aligned}
& \text { X: } 1 s^2 2 s^2 2 p^6 3 s^2 3 \mathrm{p}^3 \\
& \text { Y: } 1 \mathrm{~s}^2 2 \mathrm{~s}^2 2 \mathrm{p}^6 3 \mathrm{~s}^2 3 \mathrm{~s}^5
\end{aligned}$
Which of the following is the correct molecular formula and type of bond formed between X and Y ?
- A$\mathrm{X}_3 \mathrm{Y}$, ionic bond
- B$\mathrm{X}_2 \mathrm{Y}_3$, coordinate bond
- Correct answerC$\mathrm{XY}_3$, covalent bond
- D$\mathrm{X}_2 \mathrm{Y}$, covalent bond
Solution
$\begin{aligned}
& x: 1 s^2 2 s^2 2 p^6 3 s^2 3 p^3 \Rightarrow p \\
& y: 1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 \Rightarrow \mathrm{Cl}
\end{aligned}$
Valency of $\mathrm{p}=3$ or 5
Valency of $\mathrm{Cl}=1$
Possible molecules are $\mathrm{PCl}_3$ or $\mathrm{PCl}_5$
Both are covalent
Hence, the correct answer is option: 'C'.