Elements in the same group of the periodic table have the same: MCQ with Answer and Explanation

Explanation:
Ionic character increases with the difference in electronegativity between bonding atoms. In hydrogen halides, electronegativity decreases from F to I (F: 4.0, Cl: 3.0, Br: 2.8, I: 2.5). Thus HF has the largest electronegativity difference (1.9) and highest ionic character. The trend: HF > HCl > HBr > HI. However, HF is still a covalent polar molecule. Exam tip: Electronegativity difference > 1.7 usually indicates ionic bond.

Explanation:
Bleaching powder (CaOCl₂) reacts with dilute acids or even CO₂ from air to release chlorine: CaOCl₂ + H₂SO₄ → CaSO₄ + Cl₂ + H₂O; or with CO₂: CaOCl₂ + CO₂ → CaCO₃ + Cl₂. The chlorine gas acts as oxidizing and bleaching agent. Actually the bleaching is due to nascent oxygen produced by chlorine with water: Cl₂ + H₂O → 2HCl + [O]. But the key is chlorine liberation.

Explanation:
Chromatography separates components of a mixture based on differential affinities between a stationary phase and a mobile phase. In paper chromatography, dyes separate due to different rates of movement. Distillation is for liquids, centrifugation for density-based separation, filtration for solids from liquids. Chromatography is used in forensics, drug testing, and food coloring analysis.