Q. Which of the following statements are correct about phenolformaldehyde resin?

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Novolac or resol is a linear polymer and is used in the manufacture of adhesive.

Bakelite is a cross-linked polymer and is used in making switches and plugs.

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 prepared when $P / F < 1$, and bakelite is prepared when $P / F >1$.

Solution:

Correct answer is (a) Novolac or resol is a linear polymer and is used in the manufacture of adhesive.Correct answer is (b) Bakelite is a cross-linked polymer and is used in making switches and plugs.Correct answer is (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 $1 .$

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