Faraday's second law of electrolysis relates the masses of different substances deposited to their: MCQ with Answer and Explanation

Explanation:
Detergents do not form scum with Ca²⁺/Mg²⁺, so they clean effectively in hard water. Soaps form insoluble precipitates. Biodegradability varies; some detergents are non-biodegradable.

Explanation:
Nitrogen has 5 valence electrons; it needs 3 more to complete the octet. It shares three electrons with three hydrogen atoms, forming three covalent bonds. Therefore, valency is 3. In the case of nitrogen, covalency is 3, while its electrovalency could be 5 (losing all 5). For covalent molecules, valency = number of shared electron pairs. In N₂, valency is also 3 (triple bond).

Explanation:
Petroleum originates from microscopic marine organisms (plankton) that sank to the seabed and were transformed by heat/pressure over millions of years. Coal is from land plants.