Question

Which of the following statements are correct about phenol-formaldehyde resin?

• A. Novolac or resin is a liner polymer and is used in the manufacture of adhesive.
• B. Bakelite is a cross-linked polymer and is used in making switches and plugs.
• C. Novolac is prepared when (P/F) (phenol/formaldehyde) ratio is greater than $1$, whereas bakelite is prepared when (P/F) ratio is less than $1$.
• D. Novolac is prepared when P/F $<1$ and bakelite is prepared when P/F $>1$.

Answer 1

Answer: (A), (B), (C)

The correct options are
A Novolac or resin is a liner polymer and is used in the manufacture of adhesive.
B Bakelite is a cross-linked polymer and is used in making switches and plugs.
C Novolac is prepared when (P/F) (phenol/formaldehyde) ratio is greater than $1$, whereas bakelite is prepared when (P/F) ratio is less than $1$.

Novolac is used in the manufacturing of adhesive. Novolacs are phenol-formaldehyde resins with a $\frac{P}{F}$ ratio of greater than one.

Bakelite or polyoxybenzylmethylenglycolanhydride is an early plastic. It is a thermosetting phenol-formaldehyde resin, formed from an elimination reaction of phenol with formaldehyde having $\frac{P}{F}$ ratio is less than 1. Bakelite is used for its electrical nonconductivity and heat-resistant properties in electrical insulators, radio and telephone casings.
Hence, options A, B, and C are correct.