A white sodium salt Y gives no precipitate with BaCl2 and dilute HCl, gives a white precipitate with CaCl2 that is insoluble in acetic acid, and on warming with conc. H2SO4 evolves two colourless gases, one of which burns with a blue flame. Y also decolourises warm acidified KMnO4. Y, the moles of MnO4^- used per mole of Y and the mole ratio of the two gases from conc. acid are respectively

JEE Advanced levelSingle correct optionDifficulty 3 of 3qa055

A white sodium salt Y gives no precipitate with $BaCl X_{2}$ and dilute HCl, gives a white precipitate with $CaCl X_{2}$ that is insoluble in acetic acid, and on warming with conc. $H X_{2} SO X_{4}$ evolves two colourless gases, one of which burns with a blue flame. Y also decolourises warm acidified $KMnO X_{4}$ . Y, the moles of $MnO X_{4} X^{-}$ used per mole of Y and the mole ratio of the two gases from conc. acid are respectively

Calcium oxalate is insoluble in acetic acid, and CO with

CO X_{2}

from conc.

H X_{2} SO X_{4}

identifies oxalate.

2 MnO X_{4} X^{-} + 5 C X_{2} O X_{4} X^{2 -} + 16 H X^{+} 2 Mn X^{2 +} + 10 CO X_{2} + 8 H X_{2} O

gives 2/5 = 0.4 mol per mole. Dehydration gives CO and

CO X_{2}

in a 1:1 ratio. Carbonate would not give CO and does not decolourise permanganate.