Which of the following compounds has a coordinate bond? MCQ with Answer and Explanation

Explanation:
Azotobacter is a free-living aerobic bacterium that fixes atmospheric nitrogen in the soil, making it available to non-leguminous crops. Rhizobium is symbiotic and specific to legumes. Nitrobacter and Nitrosomonas are involved in nitrification (converting ammonia to nitrites/nitrates), not nitrogen fixation.

Explanation:
Sodium acetate (CH₃COONa) is a salt of weak acid (acetic acid) and strong base (NaOH). It hydrolyzes to produce OH⁻ ions: CH₃COO⁻ + H₂O ⇌ CH₃COOH + OH⁻, making the solution basic. NaCl (strong acid-strong base) neutral. NH₄Cl (strong acid-weak base) acidic. NaNO₃ neutral. Basic salts turn red litmus blue.

Explanation:
In electroplating, the object to be electroplated is connected as the cathode, where metal cations in the electrolyte are reduced to metal atoms and deposited as a coating. The anode is usually the plating metal, which oxidizes and dissolves, replenishing the electrolyte. For example, silver plating: cathode is the article, anode is pure silver, electrolyte is AgCN/AgNO₃.