Question

give the position isomer of pentan 2 one

Answer 1

Positional Isomer: This is Pentan-3-one. It is a positional isomer of Pentan-2-one, because the position of carbonyl has shifted from carbon no.2 to carbon no. 3, but the number of molecules of carbon, hydrogen and oxygen would remain same.

Answer 2

These are positional isomers because the ketone group is present at different carbon in both the cases.

In case of metamerism, the isomers should differ in rearrangement of alkyl groups around the polyvalent group.

That's the reason it shows metamerism also.

Hope it helps!