Question

Which of the following order is wrong?

• A. NH₃ < PH₃ < AsH₃ — Acidic
• B. Li < Be < B < C < I
• C. Al₂O₃ < MgO < CaO < K₂O — Basic
• D. Li⁺ < Na⁺ < K⁺ < Cs⁺ — Ionic radius

Hint:

Always check whether the trend is periodic or group-wise before validating orders.

Answer 1

The Correct Option is B

Step 1: Acidity of hydrides increases down the group: NH₃ < PH₃ < AsH₃ (correct) Step 2: Basic nature of oxides increases from amphoteric to strongly basic: Al₂O₃ < MgO < CaO < K₂O (correct) Step 3: Ionic radius increases down the group: Li⁺ < Na⁺ < K⁺ < Cs⁺ (correct) Step 4: Order given in option (B) is incorrect.