A schematic of the solution is shown below. The information from the question is given in black. Deductions directly from this information are given in red. Points that provide potential key information are shown in green which leads to the structures which are linked via the blue arrows to show a pathway to work them all out. There are, of course, other possible thought pathways. In this question, some key information can be worked out before looking at the reactions themselves.

The question gives a lot of data on A with MW=88 and elemental analysis data we can work out the MF = C₅H₁₂O this has an IHD = 0. Spectroscopic and reaction data suggests a tertiary alcohol.

In addition, there is key information on I. The reaction data from G suggests that I is an ester and the hydrolysis to ethanoic acid and propan-2-ol, confirms that and gives the structure of I.

D NMR spectral data could also be very helpful: H-NMR 3.6 ppm possible OH, 1.9 and 0.9 ppm peaks suggest an isopropyl group -CH(CH₃)₂ and the peak a 1.2pmm suggests 2 x CH₃, with C-NMR giving 4 C types, all below 80ppm. (i.e. no sp2)