DifferenceModerate2 marks
7(a)
Give a chemical test to distinguish between the following pairs of chemicals:
Lead nitrate solution and Zinc nitrate solution
Topic: Qualitative analysis using NaOH and NH₄OH
Previous-year question practice database
Answer
Exam answer
With excess NaOH, Pb²⁺ gives a white precipitate soluble in excess; Zn²⁺ also dissolves in excess, so use NH₄OH instead: Pb(OH)₂ remains insoluble while Zn(OH)₂ dissolves.
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