Question

Elements A and B combine to form the ionic compound \(\text{A}_{x}\text{B}_{y}\). The anions of B are arranged in hcp array and the cations of A occupy all the octahedral voids. Determine the values of x and y.

• A. \(x=1\) and \(y=1\)
• B. \(x=2\) and \(y=1\)
• C. \(x=1\) and \(y=2\)
• D. \(x=1\) and \(y=3\)

Hint:

In an hcp array, the number of octahedral voids equals the number of anions.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept
In an hcp array of \(N\) anions, there are \(N\) octahedral voids.

Step 2: Count the Ions
All octahedral voids are filled by A, so there are \(N\) cations of A and \(N\) anions of B.

Step 3: Formula
A : B \(=1:1\), so the formula is AB (NaCl-type), with \(x=1\) and \(y=1\).

Final Answer:
The values are \(x=1\) and \(y=1\). \[ \boxed{\text{(A) }\text{x = 1 and y = 1}} \]