the compound (X) is

Hence, the correct answer is option (c) 21. Acetone and acetaldehyde are differentiated by (a) NaOH + I₂ (b) [Ag(NH₃)₂] ⊕ (c) HNO₂ (d) I₂ Tollen’s test is also known as the silver mirror test and in this the given compound is treated with ammoniacal silver nitrate to give a silver coloured mirror like solution. It is used to determine the presence of aldehyde and aromatic aldehydes and for the detection of some alpha-hydroxy ketones which undergoes tautomerisation to form an aldehyde. Here, acetaldehyde is an aldehyde and acetone is not so this test can be used to distinguish between the two.