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.
`underset("Manganese dioxide")(2KMnO_(4) + H_(2)O) to 3KOH + 2MnO_(2) + 3(O)`
`underset("1-butanol")(CH_(3)-CH_(2)-CH_(2)-CH_(2)OH overset(2(O))underset("roomtemp")to underset("butanoic acid")(CH_(3)CH_(2)CH_(2)COOH + H_(2)O)`