Acidified $K_{2}C{r}_2{O}_7$ oxidizes primary alkanol to alkanal and then to alkanoic acidcidified $K_{2}C$ kanone only.
It has no effect on tertiary $\left(3^{\circ }\right)$ alkanol
$RCH{R}^{\prime }\stackrel{\frac{K,Cr,O,O}{⟶}}{⟶}$ No reaction
$3^{\circ }$ alkanol
$C{H}_{3}C{H}_{2}CH(OH)C{H}_3$ is a secondary alkanol (Butan - $2-$
ol) which will be oxidized to butanone.
$C{H}_{3}C{H}_{2}C{H}_{2}OH$ is a primary alkanol
(butan $-1-ol$ )
that is oxidized to butanal
$\left(C{H}_{3}C{H}_2{H}_{2}CHO\right)$
$C{H}_{3}C{H}_{2}C{H}_{2}C\left(C{H}_3\right)(OH)C{H}_3$ is a tertiaryalkanol (2 methylpentan $-2-01)$ which does not undergo oxidation with acidified $K_{2}C{r}_2{O}_7$.