Question

Arrange the following compounds in increasing order of their boiling points

A) b < a < c
B) a < b < c
C) c < a < b
D) c < b < a

Answer 1

Boiling point is defined as the temperature at which we get vapour pressure of liquid equals to the atmospheric pressure. When we boil a liquid it changes fro its liquid state to gaseous state. Boiling point is also referred to as the saturation point. The temperature at which the process of boiling occurs under the pressure of one bar is called standard boiling point.

Complete step-by-step answer:
Now in organic compounds the boiling points depend on the branching of the compound. The boiling point in the organic compounds increases with increase in the number of carbon atoms attached to the halides. Now if we have the same number of the carbon atoms in the compounds then we will determine its boiling point by their branching.

So the boiling of the compounds increases with the decrease in the branching. So the order of the carbocations will be for boiling point is primary>secondary>tertiary. So in this case we have same number of carbons so we will see the branching. The part b has no branching that means it has the highest boiling point. In part b we have branching as it is a secondary carbon structure so it will have a lower point than primary or case b. In part c we have a lot of branching so it will have the lowest boiling point. So the order will be c

Hence the correct answer is option ‘C’.

Note: Bromine is halogen with the atomic number 35. It is a good oxidising agent. It has the tendency to oxidise the sulfurous acid sulphuric acid. It has a strong electron affinity. Due to the weak hydration of bromide ion it is less oxidising agent than chlorine.