Explanation:
(a) The functional group present in an organic compound having the molecular formula C
5
H
10
O
2
is Carboxylic acid group, (−COOH) and its formula is C
4
H
9
COOH
(b) One example each of the compounds having the following functional groups are:
(i) Aldehyde group: Ethanal (CH
3
CHO)
(ii) Alcohol group: Methanol (CH
3
OH)
(iii) Carboxylic acid grou: Ethanoic acid (CH
3
COOH)
(iv) Halo group: Chloromethane (CH
3
Cl)
(c) One example each of the compounds having the following functional groups are:
(i) Alkene group: Ethene (CH
2
=CH
2
)
(ii) Alkyne group: Ethyne (CH≡CH).