Which of the following water purification methods can remove dissolved salts? MCQ with Answer and Explanation

Explanation:
Single superphosphate (SSP) is a phosphorus fertilizer, a mixture of monocalcium phosphate and gypsum, produced by treating rock phosphate with sulfuric acid: Ca₃(PO₄)₂ + 2H₂SO₄ → Ca(H₂PO₄)₂ + 2CaSO₄. Urea and ammonium nitrate are nitrogenous fertilizers. Potassium chloride is a potash fertilizer. Phosphorus promotes root development and flowering.

Explanation:
In CaCO₃ decomposition, the oxidation states are: Ca (+2), C (+4), O (-2) in both reactant and products, so no change—not a redox reaction. The others involve changes: Zn(0→+2), Cu(+2→0) in B; Na(0→+1), Cl(0→-1) in C; C(-4→+4), O(0→-2) in D. Redox requires change in oxidation numbers.

Explanation:
Phenolphthalein: pH range 8.3–10; colorless below 8.3, pink above. Litmus is red in acid, blue in base. Methyl orange red in acid, yellow in base. Turmeric yellow in acid, reddish-brown in base.