When tertiary butyl alcohol and 1-butanol are separately treated with a few drops of `KMnO_(4)`, in one case only the purple colour disappears and a brown precipitate is formed. Which of the two alcohols gives the above reaction and what is that brown precipitate.

Explanation

1-butanol, being primary alcohol gets oxidised by dilute `KMnO_(4)`. The brown precipitate is due to the formation of manganese dioxide.
`2KMNO_(4)+H_(2)Orarr 3KOH +underset("(brown precipitate)")underset("manganese dioxide")(2MnO_(2))+3(O)`
`underset("1 - butanol")(CH_(3)-CH_(2)-CH_(2)-CH_(2)-OH)+overset(2(O))underset("room temp.")rarr underset("butanoic acid")(CH_(3)CH_(2)CH_(2)COOH)+H_(2)O`