A short fragment of a biodegradable polyester chain (three repeat units, end groups shown) is drawn. It is formed by two different hydroxy acids. Cleaving every ester bond with water would give which pair of compounds, shown as two molecules among the structures?

AStructure A
BStructure B
CStructure C
DStructure D

Answer: C

Each unit has the O-CH(R)-CH2-C(=O) pattern, so the monomers are 3-hydroxy acids; the R groups are CH3 and C2H5. The polymer is PHBV, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and hydrolysis of the two ester bonds returns 3-hydroxybutanoic acid and 3-hydroxypentanoic acid. The 2-hydroxy, 3-hydroxyhexanoic and 4-/5-hydroxy pairs would place the hydroxyl at the wrong carbon or give a different chain length.

Practice Polymers More on Monomer from drawn repeat unit

Previous questionNext question

More questions on Monomer from drawn repeat unit

A short fragment of the polymer chain (two repeat units, end groups shown) is drawn. Which cyclic compound, among the structures shown, is t... JEE Main level
A short fragment of the polymer chain (two repeat units, end groups shown) is drawn. Which of the structures shown is the monomer from which... JEE Main level
A short fragment of a polymer chain (one repeat unit with its two end groups shown) is drawn. Which pair of monomers, shown as two molecules... JEE Main level
A short fragment of a copolymer chain (three repeat units, end groups shown) is drawn. It is a synthetic rubber made by free radical copolym... JEE Advanced level
A short fragment of a polymer chain (three repeat units, end groups shown) is drawn. Select all correct statements. JEE Advanced level
A short fragment of a polyester chain (end groups shown) is drawn. It is formed by head-to-tail esterification of a single hydroxy acid mono... JEE Advanced level