A position isomer of 2-pentanone is :A 3-Pentanone B 3-Methyl-2-butanone C 1-Pentanal D 2,2-Dimethylpropanal

To determine the position isomer of 2-pentanone, we need to analyze the structure of 2-pentanone and compare it to the given options.

The structure of 2-pentanone consists of a pentane chain with a ketone functional group (C=O) attached to the second carbon atom.

Let's examine each option:

A) 3-Pentanone: This is not a position isomer of 2-pentanone because the ketone functional group is attached to the third carbon atom, not the second.

B) 3-Methyl-2-butanone: This is not a position isomer of 2-pentanone because it contains a methyl group attached to the third carbon atom, not the second.

C) 1-Pentanal: This is not a position isomer of 2-pentanone because it contains an aldehyde functional group (C=O) instead of a ketone functional group.

D) 2,2-Dimethylpropanal: This is not a position isomer of 2-pentanone because it contains a propanal functional group (C=O) instead of a ketone functional group.

Based on the analysis, the correct answer is B) 3-Methyl-2-butanone.