Faraday's constant represents: MCQ with Answer and Explanation

Explanation:
Calcination is the process of heating a concentrated ore strongly in the absence or limited supply of air. It is typically used for carbonate ores to drive off volatile impurities like CO₂ and H₂O (e.g., CaCO₃ → CaO + CO₂). Roasting is done in the presence of excess air.

Explanation:
Ammonia (NH₃) is manufactured by the Haber process, which involves the direct combination of nitrogen and hydrogen gases at high pressure (200 atm) and moderate temperature (450°C) in the presence of an iron catalyst. The Contact process is for sulfuric acid, and Ostwald's is for nitric acid.

Explanation:
In AlCl₃, aluminium combines with three chlorine atoms. Chlorine has a valency of 1 (needs one electron to complete its octet). By the criss-cross method, Al has valency 3 because it loses three electrons to achieve a stable octet (Al³⁺). Thus, the formula is AlCl₃. Aluminium's electronic configuration is 2,8,3, so it loses three valence electrons. Exam tip: Valency equals the number of electrons lost, gained, or shared to complete octet.