Question

Give chemical tests for each:

a) Give a simple chemical test (other than colour change of an acid-base indicator) that would distinguish between propanoic acid and pentanol.

b) Give a simple chemical test (other than colour change of an acid-base indicator) that would distinguish between propanoic acid and pentanal.

c) Give a simple physical test that would distinguish between decanoic acid and sodium decanoate.

Answer 1

a)

propanoic acid --> acid

pentanol --> alcohol

Addition of NH3 (or any weak basE) will react with propanoic acid, change its pH , whereas pentanol will not react

b)

Apply for aldehyde test:

addition of potassium dichromate(VI) will turn the aldehyde to yellow solution

c)

decanoic acid and sodium decanoate:

physical test --> solubility in water/ether

the sodium decanoate should all 100% remain in the aquoeus layer

whereas the adecanoic acid should remain in both, orgnaic + aquoeus layers