Which of the following pairs can be distinguished by iodine and dilute `NaOH`?

Options

A. `n-`propyl alcohol and ethyl methyl ether
B. Benzyl alcohol and cyclohexanol
C. `t-`Butyl alcohol and `s-`butyl alcohol
D. `n-`Propyl alcohol and `n-`butyl alcohol

Answer

C

Explanation

In general, the haloform reaction is successful provide the alcohol is a methyl carbinol `(RCH(OH)CH_(3))` with at least one `H` on the carbinol `C`.
`underset(s-"butyl alcohol")(CH_(3)CH-(2)CH(OH)CH_(3))overset(X_(2),OH^(-))underset("Oxidation")(rarr)underset("not isolated")([CH_(3)CH_(2)COCH_(3)])rarr[CH_(3)CH_(2)COCX_(3)]rarrCH_(3)COO^(-)+CHX_(3)`
Acidification after oxidation converts the anion to `CH_(3)COOH`.
`(CH_(3))_(3)COHoverset(X_(2)//OH^(-))(rarr)`No reaction
A distinctive precipitate of pale yellow iodoform, `CHI_(3)`, appears if `I_(2)` is the halogen used (iodoform test).