Chemistry tests for...

Alkene

Add bromine water drop-wise at room temp. Positive test = decolourises bromine water.

Haloalkane

AgNO3, CH3CH2OH, warm. Positive test(s) = white (chloroalkane), cream (bromoalkane), yellow (iodoalkane) precipitate.

Carbonyl

2,4DNP. Positive test = orange precipitate.

Aldehyde

Tollen’s reagent, warm. Positive test = silver mirror.

Primary, secondary alcohol and aldehyde

K2Cr2O7, H+, warm. Positive test = colour change from orange to green.

Carboxylic acid

Na2CO3(aq). Positive test= effervescence.

Phenol

Two parts:

pH indicator/meter. Positive test = (pH

CO3 2-

Dilute nitric acid. Positive test = effervescence. Can be further tested by bubbling through limewater (turns milky).

SO4 2-

nitric acid (avoid false positive of carbonate)→ barium nitrate. Positive test = white precipitate.

Halide ions (X-)

HNO3, AgNO3. Positive test = white, cream or yellow precipitate.

Add dilute ammonia then concentrated ammonia. Chlorine precipitate dissolves in dilute, bromine precipitate dissolves in concentrated.

NH4+

NaOH(aq), heat. Positive test = damp red litmus paper turns blue.