$C_{4}H_{10}O$ $\xrightarrow{K_{2}Cr_{2}O_{7} / H_{2}SO_{4}} C_{4}H_{8}O$ $\xrightarrow{I_{2} / NaOH, \text{Warm}} CHI_{3}$
Here, $N$ is

Show the $\beta$-elimination reactions for the following alcohols:
$(i)$ Propyl alcohol
$(ii)$ Isopropyl alcohol
$(iii)$ Cyclohexanol
$(iv)$ Tertiary-butyl alcohol.

The decreasing order of reactivity of the following alcohols with halo acid is:
$(I)$ $CH_3OH$
$(II)$ $CH_3CH_2OH$
$(III)$ $(CH_3)_2CHOH$
$(IV)$ $(CH_3)_3COH$

Explain the acidic dehydration of alcohols with an example.

Which of the following alcohols gives white turbidity almost immediately with the Lucas reagent at room temperature?
$(i)$ $n-$Butanol
$(ii)$ $tert-$Butanol
$(iii)$ Benzyl alcohol
$(iv)$ Allyl alcohol

An organic liquid $A$ containing $C$,$H$,and $O$ has a pleasant odour with a boiling point of $78\ ^\circ C$. On boiling $A$ with conc. $H_2SO_4$,a colourless gas is produced which decolourises bromine water and alkaline $KMnO_4$. One mole of this gas also reacts with one mole of $H_2$. The organic liquid $A$ is: