Which of the following is a chemical property of a substance? MCQ with Answer and Explanation

Explanation:
In the liver, methanol is oxidized to formaldehyde, then to formic acid, which damages the optic nerve and can cause blindness or death. Ethanol is used as an antidote by competing for the enzyme alcohol dehydrogenase.

Explanation:
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.

Explanation:
Two or more substances (SO₂ and O₂) combine to form a single product (SO₃). This is a combination reaction. It is also a redox reaction and is catalyzed by V₂O₅ in the Contact process for sulfuric acid. Decomposition is the opposite (breaking down). Displacement involves replacement of an element.