The horizontal rows in the modern periodic table are called: MCQ with Answer and Explanation

Explanation:
CNG stands for Compressed Natural Gas. It is primarily methane stored at high pressure. It is considered a cleaner fuel than petrol or diesel because it produces fewer pollutants like carbon monoxide and unburnt hydrocarbons, and it leaves no residue upon combustion.

Explanation:
Boyle's law: P₁V₁ = P₂V₂. If P₂ = 2P₁, then V₂ = V₁/2. Volume is inversely proportional to pressure.

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.