An unknown alcohol is treated with the “Lucas reagent” to determine whether the alcohol is primary, secondary or tertiary. Which alcohol reacts fastest and by what mechanism:

An organic compound A upon reacting with $$N{H_3}$$ gives $$B.$$ On heating $$B$$ gives $$C.$$ $$C$$ in presence of $$KOH$$ reacts with $$B{r_2}$$ to given $$C{H_3}C{H_2}N{H_2}2.$$ $$A$$ is :

Arrange the following compounds in order of decreasing acidity :

The order of stability of the following carbocations :