Question

Natural rubber has:
A. All cis-configuration
B. All trans-configuration
C. Alternate cis and trans configuration
D. Random cis and trans configuration

Answer 1

Hint: Rubber is also called latex which has a variety of uses. It is a linear polymer having the same configuration. It consists of polymers of organic compound isoprene with water and other minor impurities.

Step by step answer: Natural rubber is also called India rubber, latex, Amazonian rubber and caucho or caoutchouc. As initially produced, it consists of polymers of the organic compound isoprene with minor impurities of other organic compounds plus water. Today, Thailand and Indonesia are two of the leading rubber producers. Types of poly-isoprene that are used as natural rubbers are classified as elastomer.
Currently, rubber is harvested mainly in the form of latex from the rubber tree or others. The latex is a sticky, milky colloid drawn off by making incisions in the bark and collecting the fluid in the vessels in a process called “tapping”. The latex then is refined into rubber that is ready for commercial processing.
Natural rubber is used extensively in many applications and products either alone or in combination with other materials. In most of its useful form, it has a large stretch ratio and high resilience and is extremely waterproof.
Natural rubber has all cis-configuration. It is a linear polymer of cis-isoprene or cis-2-methyl-1,3-butadiene which is the chemical formula of rubber.

Therefore, the correct answer is option A.

Additional information: There are various sources of rubber latex. They are Hevea brasiliensis, Congo rubber and Dandelion. Some other plants also produce forms of latex rich in isoprene polymers but they need elaborate processing to produce anything like usable rubber.
More than 28 million tons of rubber were produced in 2017 of which approximately 47% was natural. Asia was the main source of natural rubber of about 94% of output in 2005. The largest producers, Thailand, Indonesia and Malaysia together account for around 72% of natural rubber production.

Note: Rubber exhibits unique physical and chemical properties. It is an elastomer and a thermoplastic. It is a linear polymer with cis-configuration.