How does #"propionaldehyde"# differ from #"acetone"#?
They differ in the position of the carbonyl group......
Because the aldehyde group (i.e. the terminal carbonyl) is more sterically exposed, propanal should be more reactive than acetone, and indeed it is. Should propanal and acetone have different physical properties? If you are in doubt, then look up the physical properties of each isomer.