JEE Main 2016 · 10 Apr · Shift 1 · Chemistry Q51

← JEE Main 2016 · 10 Apr · Shift 1

ChemistrySingle correct+4 / -1Question 51 of 90

Sodium extract is heated with concentrated $\ce{HNO3}$ before testing for halogens because :

Silver halides are totally insoluble in nitric acid.

\ce{Ag2S}

and AgCN are soluble in acidic medium.

\ce{S^2-}

and

\ce{CN-}

, if present, are decomposed by conc.

\ce{HNO3}

and hence do not interfere in the test.

Ag reacts faster with halides in acidic medium.

Answer and worked solution

Official answer: C

Boiling with concentrated $\ce{HNO3}$ decomposes sulphide and cyanide (to $\ce{H2S}$ and HCN), which would otherwise precipitate with $\ce{Ag+}$ and mask the halide test.

Topics:Qualitative and quantitative analysis of organic compounds

← Previous question Next question →

JEE Main 2016 · 10 Apr · Shift 1, Chemistry question 51