JEE Main · 2022 · 29 Jun 2022 · Shift 2 · Practical and Analytical Chemistry

A white precipitate was formed when

BaCl_{2}

was added to water extract of an inorganic salt. Further, a gas ' X ' with characteristic odour was released when the formed white precipitate was dissolved in dilute HCl . The anion present in the inorganic salt is :

(A) $I^{-}$
(B) $SO_{3}^{2 -}$ ✓ Correct
(C) $S^{2 -}$
(D) $NO_{2}^{-}$

Answer: (B)

Solution

The test described is characteristic of sulfite ion (

SO_{3}^{2 -}

When $BaCl_{2}$ is added to a solution containing $SO_{3}^{2 -}$ , a white precipitate of $BaSO_{3}$ forms:

Ba^{2 +} + SO_{3}^{2 -} \to BaSO_{3} ↓

(white)

When this white precipitate is treated with dilute HCl, $SO_{2}$ gas is released, which has a characteristic pungent smell (burning sulfur odor):

BaSO_{3} + 2 HCl \to BaCl_{2} + H_{2} O + SO_{2} ↑

This confirms the presence of sulfite ion.

JEE Main · 2022 · 29 Jun 2022 · Shift 2 · Single correct option

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JEE Main · 2022 · 29 Jun 2022 · Shift 2 · Practical and Analytical Chemistry

Solution

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