The process of destructive distillation of coal yields:
A. Petrol and diesel
B. Only methane
C. Coke, coal tar, and coal gas
D. Graphite
Answer: Option C
Solution (By JKExamLibrary)
Heating coal in the absence of air (destructive distillation) produces coke (solid residue, high carbon), coal tar (mixture of aromatic compounds), ammoniacal liquor, and coal gas (H₂, CH₄, CO). Coke is used in blast furnace. Coal tar is a source of aromatic chemicals and pitch. Coal gas was used for lighting historically.
Explanation:
CH₄ (methane) has covalent bonds where carbon shares electrons with four hydrogen atoms. CaO (Ca²⁺ O²⁻), KCl, and NaF are ionic compounds formed by electron transfer between a metal and a non-metal. Ionic bonds form when electronegativity difference is large. Covalent bonds typically between non-metals with similar electronegativities.
Explanation:
Primary batteries are non-rechargeable; the chemical reaction that produces electricity cannot be reversed. The common dry cell (zinc-carbon battery) and alkaline batteries are primary cells. Lead-acid, Ni-Cd, and Li-ion are secondary (rechargeable) batteries where the reaction can be reversed by applying an external current.
Explanation:
CFCs release chlorine atoms under UV radiation in the stratosphere, which catalytically destroy ozone molecules. CO causes smog and is poisonous, SO₂ causes acid rain, ammonia is not a major ozone depleter. The Montreal Protocol phased out CFCs to protect the ozone layer.
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