Give simple chemical tests to distinguish between the following pairs of compounds.
$(i)$ Propanal and Propanone
$(ii)$ Acetophenone and Benzophenone
$(iii)$ Phenol and Benzoic acid
$(iv)$ Benzoic acid and Ethyl benzoate
$(v)$ Pentan$-2-$one and Pentan$-3-$one
$(vi)$ Benzaldehyde and Acetophenone
$(vii)$ Ethanal and Propanal

(N/A) $(i)$ Propanal and propanone can be distinguished by the following tests.
$(a)$ Tollen's test: Propanal is an aldehyde and reduces Tollen's reagent to silver mirror,while propanone does not.
$(b)$ Fehling's test: Propanal reduces Fehling's solution to a red-brown precipitate of $Cu_2O$,while propanone does not.
$(c)$ Iodoform test: Propanone being a methyl ketone gives a yellow precipitate of $CHI_3$ with $NaOI$,while propanal does not.
$(ii)$ Acetophenone and Benzophenone: Use the iodoform test. Acetophenone (a methyl ketone) gives a yellow precipitate of $CHI_3$ with $NaOI$,while benzophenone does not.
$(iii)$ Phenol and Benzoic acid: Use the ferric chloride test. Phenol gives a violet colouration with neutral $FeCl_3$,while benzoic acid gives a buff-coloured precipitate of ferric benzoate.
$(iv)$ Benzoic acid and Ethyl benzoate: Use the sodium bicarbonate test. Benzoic acid reacts with $NaHCO_3$ to produce brisk effervescence of $CO_2$ gas,while ethyl benzoate does not.
$(v)$ Pentan$-2-$one and Pentan$-3-$one: Use the iodoform test. Pentan$-2-$one (a methyl ketone) gives a yellow precipitate of $CHI_3$ with $NaOI$,while pentan$-3-$one does not.
$(vi)$ Benzaldehyde and Acetophenone: Use Tollen's test (benzaldehyde gives silver mirror,acetophenone does not) or iodoform test (acetophenone gives yellow precipitate,benzaldehyde does not).
$(vii)$ Ethanal and Propanal: Use the iodoform test. Ethanal $(CH_3CHO)$ gives a yellow precipitate of $CHI_3$ with $NaOI$,while propanal does not.