20 Nitrogen compounds

Question 1

The diazonium salt in (ii) reacts with an alkaline solution of phenol to produce a coloured compound, G. Draw the structure of G.

Answer 1

Question 2

Identify the components labelled F-I in the above diagram

Answer 2

F is a DC power supply

G is the anode OR positive electrode

I is the cathode OR negative electrode

H is filter paper (OR gel) soaked in buffer solution

Question 3

Compare the relative basicities of ammonia, phenylamine and compound H. Explain your answer.

Ref: 9701/42/F/M/17

Answer 3

in compound H, the alkyl groups are electron donating /have a positive inductive effect, so it is more basic than NH3

in phenylamine, the lone pair (of N) is delocalised over the aryl group / benzene ring, so phenylamine is less basic than NH3

Question 4

What is the reaction for the formation of the NO2+ ion that is used in the nitration of benzene?

Answer 4

HNO3 + 2H2SO4 -> NO2+ + 2HSO4- + H3O+

Question 5

Describe the structure and bonding of the six-membered ring in intermediate T differs from that in methylbenzene.

Answer 5

1. Bonds are only partially delocalized in T
2. Only four pi electrons in the delocalized system of T
3. Contains a carbon that is sp3 hybridized in T
4. One carbon has a bond angle of 109.5 degrees/ tetrahedral.

Question 6

What are the reactions and conditions needed to convert and NO2 side chain to NH2 side chain?

Answer 6

Concentrated HCl + Sn and heat