Which of the most suitable reagent among the following to distinguish compound (III) from the rest of the compounds?
(I) `CH_2C-=C CH`
(II) `CH_3CH_2CH_2CH_3`
(III) `CH_3CH_2C-=CH`
(IV) `CH_3CH=CH_2`

Options

A. bromine in carbon tetrachloride
B. bromine in acetic acid solution
C. Alc. `KNnO_4`
D. Ammoniacal silver nitrate

Answer

D

Explanation

Compound (III) is a terminal alkyne with acidic H atom.Unlike other compounds, it gives a white precipitate with ammoniacal silver nitrate:
`CH_3CH_2C-=CHoverset(Ag(NH_3)_2^(+)OH^(-))toCH_3CH_2C-=overline(C)overset(+)(A)g`