MolSynapsequestion bank

MolSynapse / Question bank / Polymers / Rubber and vulcanisation

JEE Advanced levelSingle correct optionDifficulty 3 of 3pl181

Ozonolysis of natural rubber followed by reductive work-up ( $Zn / H X_{2} O$ ) cleaves every $C = C$ of the 1,4-polyisoprene chain. The main product is

A $CH X_{3} - CO - CH X_{2} - CH X_{2} - CHO$ (4-oxopentanal)
B $CH X_{3} - CO - CH X_{2} - CO - CH X_{3}$ (pentane-2,4-dione)
C $OHC - CH (CH X_{3}) - CH X_{2} - CHO$ (2-methylbutanedial)
D $CH X_{3} - CO - CH X_{3}$ (propanone) and $HCHO$

Answer: A

The repeat unit is

- CH X_{2} - C (CH X_{3}) = CH - CH X_{2} X^{-}

. Cleaving the

C = C

converts

C (CH X_{3}) =

into a ketone and

= CH X^{-}

into an aldehyde. Each repeat unit therefore becomes

CH X_{3} - CO - CH X_{2} - CH X_{2} - CHO

.

Practice Polymers More on Rubber and vulcanisation

Previous questionNext question

More questions on Rubber and vulcanisation

Which of the following effects result from vulcanising natural rubber with about 3-5 percent sulfur? (One or more options may be correct.) JEE Advanced level
Match the rubber in Column I with the monomer(s) in Column II. Column I: (P) Buna-S, (Q) Buna-N, (R) neoprene, (S) natural rubber. Column II... JEE Advanced level
Buna-S is a copolymer of NEET level
Natural rubber is vulcanised by heating it with NEET level
The mass percentage of chlorine in neoprene (repeat unit -[CH2-C(Cl)=CH-CH2]-, C 12, H 1, Cl 35.5) is closest to JEE Main level
The monomer unit of natural rubber is NEET level