Condensation polymerisation generally involves a repetitive condensation reaction between two bi-functional or trifunctional monomeric units. These polycondensation reactions may result in the loss of some simple molecules as water, alcohol, hydrogen chloride, etc., and lead to the formation of high molecular mass condensation polymers. In these reactions, the product of each step is again a bi-functional species and the sequence of condensation goes on. Since, each step produces a distinct functionalised species and is independent of each other, this process is also called as step growth polymerisation.

Consider the following statements for condensation polymerization-
I. Bifunctional or polyfunctional monomers
II. Loss of each kind of functional group in each step for bifunctional species
III. Always accompanied by the release of a byproduct molecule
IV. Monofunctional or polyfunctional monomers

Which of the following are true?

I and II

III is not true because in some reactions, there is no elimination of any molecule. Besides, monofuntional monomers fail to complete the reaction. At each step of reaction, two functional groups, one of each kind, are lost.