Question

During a qualitative analysis, a student is looking for the presence of carbonate ions CO3(2-) in various solid samples. which of the following tests can verify the presence of carbonate ions?
(A) adding a dilute solution of H2S
(B) Adding a dilute solution of HCl
(C) Adding a dilute solution of NaOH
(D) Adding a dilute solution of AgNO3
(E) Adding a dilute solution of Na2SO4​

Answer 1

The correct answer is (B) Adding a dilute solution of HCl

EXPLANATION

The presence of carbonate ions can be tested by adding a dilute acid to the solution. The acid displaces Carbon (IV) oxide from the solution. Using HCl, and a carbonate of metal X.

XCO₃₍s₎ + 2HCl₍aq₎⇒ XCl₂₍aq₎+ H₂O₍l₎ + CO₂₍g₎

The gas produced is tested using calcium hydroxide to confirm whether it is carbon (IV) oxide.