4.2 NATURAL RUBBER

4.2 NATURAL RUBBER

by ANISHA Moe

​4.2 NATURAL RUBBER

Multiple Choice

The monomer of natural rubber is

• propene

• isoprene

• 2-methylpropene

• None of the above

Multiple Choice

The following formula is the unit monomer for natural rubber.

What is the IUPAC name for this monomer?

• Methylbutene

• 3-methylbut-1,3-diene

• 2-methylbut-1,3-diene

• 2-methylbut-1,4-diene

Multiple Choice

Which of the following chemicals is used to coagulate latex?

• Ethanol

• Ammonia solution

• Ethanoic acid

• Water

Multiple Choice

Coagulation of latex can be prevented by adding

• ethanoic acid

• aqueous ammonia

• sodium chloride

• ethyl ethanoate

Multiple Choice

What is the purpose of adding formic acid to latex?

• To preserve the latex

• To coagulate latex

• To improve the quality of latex

• To prevent the coagulation of latex

Multiple Choice

Figure 6 shows latex from a rubber tree. Which statements is correct about latex?

• Withstands high temperature

• Exists as a white solid at room temperature

• Coagulates when an alkali is added

• Contains a monomer called isoprene

Multiple Choice

The rubber gloves used by doctors during surgery are made from vulcanised rubber.

What property of vulcanised rubber makes it suitable to be used for making these gloves?

• Harder than unvulcanised rubber

• Stronger than unvulcanised rubber

• Heat-resistant

• Oxidation-resistant

Multiple Choice

Which of the following chemicals can be used to vulcanise natural rubber?

• Propanoic acid

• Sodium sulphite

• Sulphur monochloride

• Ammonium hydroxide

Multiple Choice

Every morning, Ali helps his mother collect latex from the rubber trees. He finds that the latex coagulated into solid after one day without adding any substances.

Which of the following statements is correct?

• latex is less elastic.

• Latex consists of rubber particles and water.

• Bacterial activity produces acid that coagulates the latex.

• Latex is easily oxidised by oxygen.

Multiple Choice

What are the properties of vulcanised rubber which cause it to be suitable for manufacturing aircraft tyres?

• Lighter than unvulcanised rubber

• More elastic than unvulcanised rubber

• Can withstand high temperature

• Resistant to oxidation

Multiple Choice

Diagram 12 shows the formation of vulcanised rubber from natural rubber.

Vulcanisation takes place by the addition of

• ethanoic acid

• sulphuric acid

• ammonia solution

• disulphur dichloride solution

Multiple Choice

Which statement is correct about rubber?

• vulcanised rubber is easily oxidised

• vulcanised rubber can withstand high temperatures

• unvulcanised rubber is stronger and harder

• unvulcanised rubber is more elastic