CBSE 2025 · Region 2 · Set 3 · Q21 · 2 marks
Give reasons for the following observations : $\displaystyle 1$ + $\displaystyle 1$(a)p-Chloronitrobenzene reacts with (aq) NaOH at $\displaystyle 443$ K to give p-nitrophenol whereas chlorobenzene reacts with the same reagent at $\displaystyle 623$ K and $\displaystyle 300$ atm .(b)Main product obtained when chloroethane reacts with KCN is propane nitrile while with Ag CN it is ethyl isocyanide.
Give reasons for the following observations : $\displaystyle 1$ + $\displaystyle 1$
(a)
p-Chloronitrobenzene reacts with (aq) NaOH at $\displaystyle 443$ K to give p-nitrophenol whereas chlorobenzene reacts with the same reagent at $\displaystyle 623$ K and $\displaystyle 300$ atm .
(b)
Main product obtained when chloroethane reacts with KCN is propane nitrile while with Ag CN it is ethyl isocyanide.
Marking-scheme solution
(a)
Due to electron withdrawing nature of -NO2 group.
(b)
KCN is predominantly ionic and both carbon and nitrogen atoms can donate electron pairs,
the attack takes place mainly through carbon atom as C—C bond is more stable than C—N bond.
However, AgCN is mainly covalent in nature and nitrogen is free to donate electron pair forming
isocyanide as the main product.
Haloalkanes and HaloarenesChemical Reactions of Haloalkanes and HaloarenesUnderstandvery_short_answermedium
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CBSE Class 12 Chemistry past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.