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प्रश्न
The salt whose aqueous solution will turn blue litmus to red is:
(a) ammonium sulphate
(b) sodium acetate
(c) sodium chloride
(d) potassium carbonate
उत्तर
ammonium sulphate
Ammonium sulphate [(NH4)2SO4] is formed from a weak base, ammonium hydroxide (NH4OH), and a strong acid, sulphuric acid (H2SO4). On dissolving in water, (NH4)2SO4 hydrolyses to form more H+ ions than OH- ions. As the aqueous solution of the salt (NH4)2SO4 is acidic, it turns blue litmus red.
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