Which two compounds have the same molecular formula but different chemical and physical properties?
(1) CH3CH2Cl and CH3CH2Br
(2) CH3CHCH2 and CH3CH2CH3
(3) CH3CHO and CH3COCH3
(4) CH3CH2OH and CH3OCH3
(1) CH3CH2Cl and CH3CH2Br
(2) CH3CHCH2 and CH3CH2CH3
(3) CH3CHO and CH3COCH3
(4) CH3CH2OH and CH3OCH3