A solution of the group V carbonates in hot dilute acetic acid is treated with K2CrO4 solution. A yellow precipitate forms. The precipitate and the cation it confirms are

JEE Main levelSingle correct optionDifficulty 2 of 3qc123

A solution of the group V carbonates in hot dilute acetic acid is treated with $K X_{2} CrO X_{4}$ solution. A yellow precipitate forms. The precipitate and the cation it confirms are

In acetic acid medium the chromate concentration is low because

CrO X_{4} X^{2 -}

is partly converted to

HCrO X_{4} X^{-}

/dichromate. Only the least soluble chromate,

BaCrO X_{4}

, precipitates:

Ba X^{2 +} + CrO X_{4} X^{2 -} BaCrO X_{4}

(yellow).

SrCrO X_{4}

and

CaCrO X_{4}

stay in solution, and barium dichromate is soluble.