Question

What are the uses of glass/rubber tubes in the laboratory?
(A) It helps cold water to flow in and out of the condenser to allow heated water to vaporize.
(B) For liquid and gases in the experiment, rubber stoppers are used as plugs in the flask.
(C) Rubber tubing is always connected to a condenser, helps in distillation
(D) All of these

Answer 1

Hint: Glass tubes are hollow cylindrical shaped tubes usually used in the laboratory. Glass tubes used in laboratories are usually made of borosilicate glass or fused quartz.

Complete Step by step answer:
- The advantages of borosilicate glass are:
(i) Better optical clarity
(ii) Low Coefficient of thermal expansion, thus less prone to cracking than usual glass
(iii) It contains boron trioxide which makes it thermal shock resistant
(iv) They are corrosion resistance.
- They help in the passage of cold water from condensers to vaporize the hot water. In laboratories, Condensers are a lab apparatus used to condense vapors into liquids.
- Rubber stoppers can be used as plugs in the flasks for creating an airtight or liquid- tight seal.
- Rubber stoppers can be of different sizes according to the size of glass tubes.
- Rubber tubing is used for the flow of fluids and gases.
- It is generally connected to condensers which are used in the distillation process.
- Rubber tubing acts as an inlet and outlet of cold water from the condensers. Also, it acts as a passage of return of heated water vapor in condensers in its liquid state.
 So, the correct answer is option D.

Note: Distillation is the process of separating the components or substances from a liquid mixture by selective boiling and condensation. Two major types of distillation are simple distillation and fractional distillation. Distillation is used to separate the volatile liquid from non- volatile impurities or two volatile liquids having a significant boiling point difference. When two liquids have different boiling points, they vaporize at different temperatures. The vapors condense and the two liquids are collected separately. For example, chloroform and aniline having boiling points 334 K and 457 K can be separated by distillation. More volatile chloroform evaporates first and is collected in the receiver. Aniline is left in the distillation flask.