Right just to clear some things up. For the structural isomers question is was 4. As the methyl group can have a cl attached, but that's the same as 1-chloro,2-methylheptane. So it's 4. I put 5 stupidly, because I didn't think about the methyl group being the same.
For the aldehyde/ketone, it said "Suggest a possible structure" that means you should get the mark for both.
As for the hydrolysing. Hydrolysis is when the OH attaches, have you not done Alkaline and Acid hydrolysis of halogenoalkanes before? I put that the C-Cl and C-F bonds are too strong to be broken just by water so increased temperature and acid/base is needed to weaken the bond.
Hydrolysis =/= dissolving sorry.