Question

1. Is the Tollen’s test qualitative or quantitative? Explain

Answer 1

Tollen's test is a qualitative test.

It uses just to differentiate between aldehyde and ketone in carbonyl compound.The test occur with the tollen's reagent by precipitate of silver mirron.With this bright mirror we can say the test is positive not to how much silver atom precipitated.Just seeing this silver mirror we confirm that the solution must contain the aldehyde containing compound(some times alfa bita unsaturated ketone) not the ketone.

In a test tube this diaminesilver salt reacts with the aldehyde and Ag precipitate occur with a bright silver mirror on inner surface of the reaction vessel.

Tollens' Reagent Step 1: Sodium hydroxide is added to silver nitrate until a light brown precipitate of silver oxide is formed. 2AgNO + 2NaOH - > Ag,0 + 2NaNO3 + H,O Silver nitrate Sodium Silver oxide Sodium Water hydroxide (brown ppt.) nitrate Step 2: Concentrated ammonia solution is added to the silver oxide until the latter completely dissolves forming a diaminesilver (1) complex. Ag,0 + 4NH, + HO - > 2[Ag(NH,), OH Silver oxide Ammonia Water diaminesilver(t) hydroxide (Tollens' reagent)

Tollens' Test + 2[Ag(NH,)ⓇoH® + 4,0 R-C-H Aldehyde diaminesilver(1) hydroxide Water o R-C-OH + 2Ag + 4NH, + 2H,0 s Carboxylic acid Silver Ammonia Water Chemistry Learner.com

So with this test we can easily differentiate between aldehyde and ketone qualitatively just seeing the characteristic bright silver mirror not calculating any other parameter.

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