The structure of diamond is: MCQ with Answer and Explanation

Explanation:
In NO₂, each oxygen has valency 2; with two oxygens, total combining capacity = 4. Thus nitrogen's covalency is 4. The structure involves a coordinate bond. Oxidation state of N is +4. Valency is number of bonds formed: N forms two single bonds and one coordinate bond with O, total 4 bonds. In NO, valency is 2.

Explanation:
The unwanted earthy or sandy impurities present in an ore are called gangue (or matrix). Flux is added during smelting to react with these impurities, and the resulting fused mass is called slag, which is lighter and floats on top of the molten metal for easy removal.

Explanation:
Catalytic converters use precious metals like platinum, palladium, and rhodium as catalysts to convert toxic exhaust gases (CO, NOx, unburnt hydrocarbons) into less harmful substances (CO₂, N₂, H₂O) before they are released into the atmosphere. These metals are chosen for their high catalytic activity and durability.