Multiple choice

Assertion: Natural rubber is a cis-1,4-polyisoprene. Reason: On vulcanization, rubber becomes softer.

Directions: In the following question there are two statements, Assertion (A) and Reason (R), consider both the statements independently and mark your answers as under:
A and R both are correct and R is correct explanation of A.
A and R both are correct and R is not correct explanation of A.
A is correct and R is incorrect.
A is incorrect and R is correct.
A and R both are incorrect.

  1. A and R both are correct and R is the correct explanation of A.

  2. A and R both are correct and R is not the correct explanation of A.

  3. A is correct and R is incorrect.

  4. A is incorrect and R is correct.

  5. A and R both are incorrect.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Both assertion as well as reason statement is true. Natural rubber may be considered as a linear polymer of isoprene (2-methyl-1, 3 butadiene) and is also called as cis-1, 4-polyisoprene. On vulcanization, sulphur forms cross links at the reactive sites of double bonds and thus, the rubber gets stiffened. Thus, this option is correct.

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