(I) `CH_(3)-CH_(2)-CH_(2)-CH_(2)-OH`
(II) `CH_(3)-CH_(2)-underset(underset(OH)(|))(C H)-CH_(3)`
(III) `CH_(3)- underset(underset(OH)(|))overset(overset(CH_(3))(|))(C )-CH_(3)`
(IV) `CH_(3)- underset(underset(CH_(3))(|))(C H)-CH_(2)-OH`
(V ) `CH_(3)-CH_(2)-O-CH_(2)-CH_(3)` (VI) `CH_(3)-O-CH_(2)-CH_(2)-CH_(3)` (VII) `CH_(3)-O- underset(underset(CH_(3))(|))(C H)-CH_(3)`
Identify the pairs of compounds that represents position isomerism

Explanation

In these, there are functional group same but the position of functional group is different. (I) and (II) are position isomers.
(I) `underset("Butan-1-ol")(CH_(3)-CH_(2)-CH_(2)-CH_(2)-OH)`
(II) `underset("Butan-2-ol")(CH_(3)-CH_(2)-underset(underset(OH)(|))(C H)-CH_(3))`
In the following same function group present in both but the carbon chain is different so, they are chain isomer
(III) `underset("2-methyl prop-2-ol")(CH_(3)-underset(underset(OH)(|))overset(overset(CH_(3))(|))(C )-CH_(3))`
(IV) `underset("2-methyl-propane-2-ol")(CH_(3)-underset(underset(CH_(3))(|))(CH)-CH_(2)-OH)`
(VI) and (VII) both are ether but carbon chain is different so, (VI) and (VII) are chain isomers.
(VI) `underset("Methoxy propane")(CH_(3)-O-CH_(2)-CH_(2)-CH_(3))`
(VII) `underset("Methoxy isopropane")(CH_(3)-O-underset(underset(CH_(3))(|))(CH)-CH_(3))`