Which of the following will not form a yellow precipitate on heating with an alkaline solution of iodine?

Options

A. `CH_(3)CH(OH)CH_(3)`
B. `CH_(3)CH_(2)CH(OH)CH_(3)`
C. `CH_(3)OH`
D. `CH_(3)CH_(2)OH`

Answer

C

Explanation

Only those alcohols which have the following structure.
`R-underset(H)underset(|)overset(OH)overset(|)(C )-CH_(3)`
where `R` is a `H` atom or only alkyl or aryl group, gives iodoform test
`CH_(3)CH(OH)CH_(3)+I_(2)rarrCH_(3)COCH_(3)+2HICH_(3)COCH_(3)+3I_(2)+4NaOHrarrunderset(ppt.)underset(Yellow)(CHI_(3))darr`
(2) `CH_(3)CH_(2)CH(OH)CH_(3)+I_(2)rarrCH_(3)CH_(2)COCH_(3)+2HICH_(3)CH_(2)COCH_(3)+3I_(2)+4NaOHrarrunderset(ppt.)underset(Yellow)(CHI_(3))darr+3NaI+CH_(3)CH_(2)COONa+3H_(2)O`
(3) `CH_(3)OH+I_(2)rarrunderset(NO reaction)underset(darrI_(2)//NaOH)(HCHO+2HI)`
(4) `CH_(3)CH_(2)OH+I_(2)rarrCH_(3)CHO+2HICH_(3)CHO+3I_(2)+4NaOHrarrunderset(ppt.)underset(Yellow)(CHI_(3))darr+HC CONa+3NaI+2H_(2)O`