(1) and (2), (1) and (3), (1) and (4), (1) and (5), (1) and (6), and (1) and (7) are functional isomers.
(2) and (3), and (3) and (4) are position isomers.
(2) and (4) are chain isomers.
(2) and (5), (3) and (5), (4) and (5), (2) and (6), (3) and (6), (4) and (6), (2) and (7), (3) and (7), (4) and (7), (5) and (7), and (6) and (7) are position isomers.
(II)
(1) and (2) are positional isomers, (1) and (3) are chain isomers,
(2) and (3) are position and chain isomers.