Washing soda (Na₂CO₃·10H₂O) is manufactured by Solvay process. Its aqueous solution is:
A. Acidic
B. Neutral
C. Amphoteric
D. Basic
Answer: Option D
Solution (By JKSSB Mock Tests)
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:
Washing soda (Na₂CO₃) reacts with Ca²⁺ and Mg²⁺ ions in hard water to form insoluble carbonates: Ca²⁺ + Na₂CO₃ → CaCO₃↓ + 2Na⁺. Similarly MgCO₃. These precipitates are removed, softening the water. Ion exchange uses zeolites or resins. Boiling removes only temporary hardness. Distillation is expensive.
Explanation:
Beta rays (β) consist of high-speed, high-energy electrons (β⁻) or positrons (β⁺) emitted from the nucleus during radioactive decay. In standard beta decay, a neutron converts into a proton and an electron, and the electron is ejected from the nucleus.
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