Question

write the structural formula for. 1) But-2-en-1-ol. 2) pent-2-ene-1.5-dial​

Answer 1

see the above attachment

Answer 2

The structures are as follows.

1. In case of but-2-ene-1-ol the word but signifies that the compound has four carbon atoms. It has one double bond between C-2 and C-3. It has one hydroxyl group at C-1.
2. In case of pent-2-ene-1,5-diol, the word pent signifies that the compound has five carbon atoms. It has one double bond between C-2 and C-3. It has two hydroxyl groups at C-1 and C-5.