Question

Of the following compounds, how many will react with Tollen's reagent?

Answer 1

Compounds containing aldehyde group $(-CHO)$ respond positively with Tollens' reagent. $1^o$ or $2^o$ alpha hydroxy ketones and terminal alkynes also gives Tollens' test.
(i) and (v) are aldehydes which give postive test.
(iii) also performs this test.
(vi) and (viii) are hemiacetal which also present in equilibrium with its aldehyde form so they will also give this test.
(ix) is terminal alkene and gives positive test.