Yellow compound of lead chromate gets dissolved on treatment with hot NaOH solution. The product of lead formed is a:
Tetraanionic complex with coordination number six
Neutral complex with coordination number four
Dianionic complex with coordination number six
Dianionic complex with coordination number four
Correct answer:D
Standard Method
Given: Yellow lead chromate dissolves in hot NaOH solution.
Find: The nature of the lead product formed.
Lead chromate is . In hot excess NaOH, lead forms the soluble complex
So the reaction gives a dianionic lead complex.
Since four hydroxide ligands are attached to lead, the coordination number is .
Therefore, the product of lead formed is a dianionic complex with coordination number four. The correct option is D.
The solution identifies the lead product as , which has charge and coordination number .
Reaction-Based Identification
Given: reacts with hot excess NaOH.
Find: The type of lead complex produced.
From the reaction described in the solution:
The complex contains four hydroxide ligands around lead, so its coordination number is . Its overall charge is , so it is dianionic.
Hence, the correct description is dianionic complex with coordination number four.
Assuming that dissolution in NaOH produces a neutral hydroxide species is incorrect because the solution explicitly forms . Always check the overall charge of the complex.
Confusing the number of hydroxide ligands with some other oxidation-state argument leads to the wrong coordination number. Here, four ligands mean coordination number .
Selecting the option with coordination number six by analogy with other metal complexes is incorrect. Use the actual complex given in the reaction, not a memorized general trend.
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