Assertion (A): Magnesium oxide is a basic oxide. Reason (R): Metals on reaction with oxygen form acidic oxides. MCQ with Answer and Explanation

Assertion (A): Magnesium oxide is a basic oxide. Reason (R): Metals on reaction with oxygen form acidic oxides.
A. Both A and R are true, but R is not the correct explanation of A
B. Both A and R are true, and R is the correct explanation of A
C. A is false, but R is true
D. A is true, but R is false
Answer: Option D
Solution (By JKExamLibrary)
Magnesium oxide (MgO) is a basic oxide because it reacts with acids to form salt and water, e.g., MgO + 2HCl → MgCl₂ + H₂O. However, Reason is false: Metals generally form basic oxides, not acidic oxides. Non-metals form acidic oxides (e.g., SO₂, CO₂). Some metals like Al, Zn form amphoteric oxides. So A is true, R false. Exam tip: Metal oxides are usually basic; non-metal oxides are acidic.

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