Question

Give two reaction in which benzene ring is not retained

Answer 1

There are many more... but these are what came to mind.
Hope they are correct and suffice enough .

Answer 2

Hey dear,
Benzene is a 6-C cyclic structure with alternate double bonds.

● Reactions -
1) Benzene to cyclohexane -
Benzene can be reduced to cyclohexane with the help of Ni/H2.
C6H6 + 3H2 --> C6H12

All 3 double bonds in ring are reduced here.

2) Benzene to benzoquinone -
Benzene can be oxidized to benzoquinone with the help of acidic K2Cr2O7.
C6H6 + 3[O] --> C6H4O2 + H2O

Only 1 double bond is lost in this reaction.

Hope this helps you.