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An aqueous solution of a salt gives a white precipitate when mixed with aqueous silver nitrate and when mixed with dilute sulfuric acid - AQA - A-Level Chemistry - Question 16 - 2019 - Paper 3
Question 16
An aqueous solution of a salt gives a white precipitate when mixed with aqueous silver nitrate and when mixed with dilute sulfuric acid. Which could be the formula ... show full transcript
Worked Solution & Example Answer:An aqueous solution of a salt gives a white precipitate when mixed with aqueous silver nitrate and when mixed with dilute sulfuric acid - AQA - A-Level Chemistry - Question 16 - 2019 - Paper 3
Step 1
Identifying the Precipitate with Silver Nitrate
Answer
When an aqueous solution of a salt is treated with aqueous silver nitrate, a white precipitate indicates the formation of silver chloride (AgCl). Therefore, the salt must contain chloride ions (Cl⁻). Only BaCl₂ and KCl provide chloride ions.
Step 2
Testing with Dilute Sulfuric Acid
Answer
When the aqueous salt is mixed with dilute sulfuric acid, a white precipitate suggests the formation of barium sulfate (BaSO₄), indicating the presence of barium ions (Ba²⁺). This means the suitable salts can either be BaCl₂ or Sr(NO₃)₂, but Sr(NO₃)₂ does not yield chloride ions with silver nitrate.
Step 3