Q113 / 200 · MHT CET - Medical 2026 (26 April Shift 1) · Chemistry
A compound is formed by two elements X and Y. The atoms of element Y form a hcp structure. The atoms of element X occupy $1/3$ of octahedral voids. What is the formula of a compound?
- Correct answerA$\text{XY}_3$
- B$\text{XY}$
- C$\text{X}_2\text{Y}$
- D$\text{X}_2\text{Y}_3$
Solution
Let the number of atoms of element Y in the hcp lattice be $N$.
The number of octahedral voids in a close-packed structure is equal to the number of atoms in the lattice, which is $N$.
Since atoms of element X occupy $\dfrac{1}{3}$ of the octahedral voids, the number of atoms of X is $\dfrac{N}{3}$.
The ratio of the number of atoms of X to that of Y is $\dfrac{N}{3} : N = 1 : 3$.
Therefore, the formula of the compound is $\text{XY}_3$.
Answer: $\text{XY}_3$
The number of octahedral voids in a close-packed structure is equal to the number of atoms in the lattice, which is $N$.
Since atoms of element X occupy $\dfrac{1}{3}$ of the octahedral voids, the number of atoms of X is $\dfrac{N}{3}$.
The ratio of the number of atoms of X to that of Y is $\dfrac{N}{3} : N = 1 : 3$.
Therefore, the formula of the compound is $\text{XY}_3$.
Answer: $\text{XY}_3$
Hence, the correct answer is option: 'A'.