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JEE Main levelSingle correct optionDifficulty 2 of 3qc022

A yellow precipitate is formed when $K X_{2} CrO X_{4}$ is added to an acetic acid solution of a cation. The precipitate is insoluble in dilute acetic acid but dissolves in $NaOH$ . The cation is

A $Pb X^{2 +}$ (giving $PbCrO X_{4}$ )
B $Cu X^{2 +}$ (giving $CuCrO X_{4}$ )
C $Cd X^{2 +}$ (giving $CdCrO X_{4}$ )
D $Bi X^{3 +}$ (giving $Bi X_{2} (CrO X_{4}) X_{3}$ )

Answer: A

Pb X^{2 +} + CrO X_{4} X^{2 -} PbCrO X_{4}

is the standard yellow confirmation of lead. It does not dissolve in dilute acetic acid and dissolves in

NaOH

as plumbite. The other cations do not give a yellow chromate precipitate under these conditions.

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