Hard water does not produce good lather with soap because it contains: MCQ with Answer and Explanation

Explanation:
Urea, CO(NH₂)₂, is a straight nitrogenous fertilizer with about 46% N. It contains no phosphorus or potassium. It is converted to ammonium carbonate in soil by urease enzyme, then to nitrates.

Explanation:
Thermosets (e.g., Bakelite) form extensive cross-links between polymer chains, making them rigid. Heating breaks bonds but degrades, not remolds. Thermoplastics are linear/branched.

Explanation:
Highly reactive metals (K, Na, Ca, Mg, Al) are extracted by electrolysis of their fused (molten) salts because chemical reducing agents cannot reduce their ores. For sodium, Down's process: electrolysis of molten NaCl with CaCl₂ to lower melting point. Iron is extracted by smelting (blast furnace). Copper and zinc can be extracted by reduction with coke or electrolytic refining of impure metal.