Which indicator is most suitable for the titration of a weak acid with a strong base? MCQ with Answer and Explanation

Explanation:
pH difference = 3 units. Since pH is logarithmic (base 10), [H⁺] ratio = 10³ = 1000. So pH 2 solution has 1000 times greater H⁺ concentration, making it 1000 times more acidic.

Explanation:
Urea is synthesized by reacting ammonia and carbon dioxide under high pressure and temperature: 2NH₃ + CO₂ → NH₂COONH₄ (ammonium carbamate) → (NH₂)₂CO + H₂O. This is the Bosch-Meiser urea process. It is the most concentrated solid nitrogenous fertilizer. Urea is also used in animal feed, plastics, and pharmaceuticals.

Explanation:
Calcium (Ca, Z=20) has configuration 2,8,8,2. 4 shells → Period 4; 2 valence electrons → Group 2. Mg is Group 2, Period 3. Sr is Group 2, Period 5. Be is Group 2, Period 2.