To understand the structural rigidity of the monomers used in polyester fibres, determine how many p — Polymers Chemistry Question

💡 Solution & Explanation

Terephthalic acid is benzene-1,4-dicarboxylic acid ($HOOC-C_6H_4-COOH$). The central benzene ring contains 3 alternating pi ($\pi$) bonds. Each of the two carboxylic acid groups ($-COOH$) contains 1 pi ($\pi$) bond in the $C=O$ double bond. Total $\pi$ bonds = $3 + 2 = 5$.