Washing soda (Na₂CO₃·10H₂O) is manufactured by Solvay process. Its aqueous solution is:
A. Basic
B. Amphoteric
C. Acidic
D. Neutral
Answer: Option A
Solution (By JKExamLibrary)
Sodium carbonate is a salt of strong base (NaOH) and weak acid (H₂CO₃). On hydrolysis, it gives OH⁻ ions: CO₃²⁻ + H₂O ⇌ HCO₃⁻ + OH⁻, making the solution basic. pH ~11. It turns red litmus blue. It is used for softening hard water and in detergents. NaHCO₃ solution is also mildly basic. Salts of strong acid + strong base are neutral (NaCl). Salts of weak base + strong acid are acidic (NH₄Cl).
Explanation:
Green manure refers to crops (like sunn hemp or dhaincha) that are grown specifically to be plowed back into the soil while they are still green. This decomposing plant material enriches the soil with organic matter, nitrogen, and other nutrients, improving soil structure and fertility.
Explanation:
While Democritus proposed the philosophical concept of the atom in ancient Greece, John Dalton formulated the first scientifically based atomic theory in 1803. His theory stated that elements are composed of indivisible atoms, atoms of the same element are identical, and compounds form from atoms combining in fixed ratios.
Explanation:
Water breaks down into hydrogen and oxygen when electricity is passed (electrolysis). A single reactant yields two or more products, hence decomposition. It is also a redox reaction. Combination is the opposite; displacement involves replacing an ion.
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