[mana]

hi all
the solubility of 3-pentanal is more than 2-pentanal and it is more than 1-pentanal in water
can you tell me why? is it because of steric strain

[mjc123]

You can't have 2- or 3- pentanal; an aldehyde must be at a chain end. Do you mean pentanol? Or pentanone?

[jeffmoonchop]

if you mean pentanol or pentanone the solubility of pentan-1-ol will be the least because you have a very polar end and a very non-polar end. The one end would dissolve in water readily but the other would be hydrophobic. pentan-3-ol will be the most soluble because the non polar ends will be more polar than the non polar end of pentan-1-ol due to the close proximity of the alcohol group.

[Babcock_Hall]

Steric strain is an unusual concept to invoke when discussing solubility.  I would examine the molecules in question for whether or not they are hydrogen bond acceptors and whether or not they are hydrogen bond donors.

[mana]

yes you are right, it is pentanol, and  thanks for all the replies