Verified Solution • 2025–26 Session moderate

QJEEM24Ch7f8e: JEE Main 2024 Chemistry - Class 12 JEEM24Ch7f8e Solution: During the detection of acidic radical present in a salt, a…

During the detection of acidic radical present in a salt, a student gets a pale yellow precipitate soluble with difficulty in NH4OH\mathrm{NH}_4 \mathrm{OH} solution when sodium carbonate extract was first acidified with dil. HNO3\mathrm{HNO}_3 and then AgNO3\mathrm{AgNO}_3 solution was added. This indicates presence of :

Multiple Choice Options

  • A I−\mathrm{I}^{-}
  • B CO32−\mathrm{CO}_3{ }^{2-}
  • C Cl−\mathrm{Cl}^{-}
  • D Br−\mathrm{Br}^{-}

Step-by-Step Verified Solution

The Br−\mathrm{Br}^{-} ion present in the salt gives pale yellow ppt. of AgBr\mathrm{AgBr} with AgNO3\mathrm{AgNO}_3 , insoluble in dil HNO3\mathrm{HNO}_3 but partially soluble in aq. NH4OH\mathrm{NH}_4 \mathrm{OH} .

Br−+AgNO3→AgBr↓ Pale yellow +NO3−\mathrm{Br}^{-}+\mathrm{AgNO}_3 \rightarrow \underset{\text { Pale yellow }}{\mathrm{AgBr} \downarrow}+\mathrm{NO}_3^{-}

AgBr+2NH4OH→[Ag(NH3)2]Br Partially soluble +2H2O\mathrm{AgBr}+2 \mathrm{NH}_4 \mathrm{OH} \rightarrow \underset{\text { Partially soluble }}{\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right] \mathrm{Br}}+2 \mathrm{H}_2 \mathrm{O}

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