Chem alevel help

Im struggling to understand questions 4ii:
https://www.physicsandmathstutor.com/pdf-pages/?pdf=https%3A%2F%2Fpmt.physicsandmathstutor.com%2Fdownload%2FChemistry%2FA-level%2FTopic-Qs%2FEdexcel%2F19-Modern-Analytical-Techniques-II%2FSet-G%2FNMR%2520Spectroscopy.pdf

If anyone understands pleasee explain to me. i read the mark scheme and i just dont get it. (mark scheme found if you scroll down)

So 2,4-DNPH produces an orange precipitate for carbonyls, so that will form for both compounds. It is not letting you use Tollen's to find the aldehyde, so instead you need to melt both products and measure the boiling points. As they are different products they give different boiling points, so you can compare both of these boiling points to known values (you can google) and find which one is which. Hope this helps x

im so silly i needed help with 4iii LOL. Thank you so much for ur help ur amazing!!. if u do understand 4iii however can you please help me with it?