Question

A solid compound XY has NaCl structure. If the radius of the cation is 100 pm, the radius of the anion \( Y^{1-} \) will be

• A. 141.5 pm
• B. 153.5 pm
• C. 122.5 pm
• D. 165.7 pm

Hint:

In ionic compounds with NaCl structure, the cation-to-anion radius ratio is approximately 0.5.

Answer 1

The Correct Option is C

For a NaCl structure, the ratio of the radii of the cation and anion is approximately 0.5. Thus, the radius of the anion can be calculated as: \[ r_{\text{anion}} = 2 \times r_{\text{cation}} = 2 \times 100 \, \text{pm} = 122.5 \, \text{pm}. \]

Step 2: Conclusion.
The correct radius of the anion is \( 122.5 \, \text{pm} \), corresponding to option (c).