Class 12th

Kindly go through the solution

HVZ reaction:

Cannizzaro reaction is shown by aldehydes containing no a–H atoms

Zn²⁺ has no unpaired electron and colourless in aqueous solution.

Homoleptic complexes in which a metal is bound to only one kind of donor groups/ligands.

In aniline –NH₂ is strong activating group due to presence of lone pair in nitrogen.

Aniline does not show Friedel-Craft alkylation reaction, because anhydrous AlCl₃ and aniline form salt together

[Ni (H₂O)₆]²⁺ Þ Ni²⁺ is octahedral and [Ni (CN)₄]^2– is square planar.

In [Ni (H₂O)₆]²⁺ Þ Ni²⁺ has two unpaired electrons and in [Ni (CN)₄]^2– Þ Ni²⁺ has no unpaired electrons. [Ni (H₂O)₆]²⁺ is coloured as it absorbs red light due to suitable d-d transition and complementary light emitted is green.

[Ni (CN)₄]^2– has strong field ligand so the electrons of Ni²⁺ pair up and it is colourless as it cannot absorb light from visible region.

KCN   + CN^–

            R – X + KCN  R – CN + KX

            R – X + AgCN  R – NC + AgX

            KCN is ionic therefore ionised and attack occurs through carbon.

            AgCN is covalent therefore attack starts with Nitrogen.