A white anhydrous salt Y gives an apple-green flame, a white precipitate with dilute H2SO4 insoluble in HCl, and a yellow precipitate with K2CrO4 in acetic acid. Y contains one anion, either Cl-, Br- or NO3-. When 2.08 g of Y is treated with excess dilute H2SO4, 2.33 g of BaSO4 (M = 233) is obtained. Y is

JEE Advanced levelSingle correct optionDifficulty 3 of 3qc214

A white anhydrous salt Y gives an apple-green flame, a white precipitate with dilute $H X_{2} SO X_{4}$ insoluble in HCl, and a yellow precipitate with $K X_{2} CrO X_{4}$ in acetic acid. Y contains one anion, either $Cl X^{-}$ , $Br X^{-}$ or $NO X_{3} X^{-}$ . When $2.08 g$ of Y is treated with excess dilute $H X_{2} SO X_{4}$ , $2.33 g$ of $BaSO X_{4}$ ( $M = 233$ ) is obtained. Y is

The flame and precipitates show

Ba X^{2 +}

. BaSO4 moles =

2.33/233 = 0.0100

, so Y has molar mass

2.08/0.0100 = 208 g/mol

BaCl X_{2}

137 + 71 = 208

;

Ba (NO X_{3}) X_{2}

= 261;

BaBr X_{2}

= 297.

BaCO X_{3}

(197) is excluded because the anions are limited to the three given and it would also effervesce.