Question

how to detect the presence of No2 group in benzene ring?

Answer 1

Presence of a nitro group in a benzene ring

• (a) deactivates the ring towards electrophilic substitution
• (b) activates the ring towards electrophilic substitution
• (c) renders the ring basic
• (d) deactivates the ring towards nucleophilic substitution

Furthermore, it can be detected by Mulliken's and Barker test in which sample is added in a test tube along with alcohol, calcium chloride, zinc dust then this is boiled and then filtered it in Tollen's reagent, this will give black or grey precipitates.

Answer 2

Nitro group: They are explosive due to strong electron-withdrawing.

The C−H bonds adjacent can be acidic.

Benzene ring: The six carbon atoms including three double bonds which forms a structure of a ring is referred to as a benzene ring.

The presence of a No2 group in a benzene ring can be identified by,

• Deactivation of the benzene ring
• No electrophilic substitution.

Hence, The No2 group is an electron withdrawing group and so it deactivates the ring towards electrophilic substitution.