Bleaching powder (CaOCl₂) releases chlorine when treated with: MCQ with Answer and Explanation

Explanation:
Arsenic (As) is a metalloid, showing properties of both metals and non-metals. It is in group 15, period 4. Sodium and calcium are metals. Oxygen is a non-metal. Metalloids: B, Si, Ge, As, Sb, Te. They are semiconductors and form amphoteric oxides.

Explanation:
CO has a triple bond: one sigma and two pi bonds, with a coordinate covalent character where oxygen donates a lone pair to carbon, forming a bond similar to triple bond. Total shared electrons = 6 (three pairs). Lewis structure shows :C≡O: with formal charges. The bond order is 3. It is isoelectronic with N₂ and CN⁻.

Explanation:
1/4 = (1/2)², so 2 half-lives = 40 days → half-life = 20 days. After 1 half-life 1/2 remains, after 2 half-lives 1/4.