Applied Chemistry Multiple Choice Questions on “Selection of Lubricants”.
1. A high temperature lubricants used may undergo ________
a) vulcanization
b) volatilization
c) lubrication
d) combustion
Answer: b
Clarification: A high temperature lubricants used may undergo volatilization. The vulcanization is the process of rubber in presence of sulphur.
2. For heavy cutting, the effective lubricants are _________
a) coconut oils
b) cutting oils
c) kerosene
d) diesel
Answer: b
Clarification: The cutting oils are most suitable oils for heavy cutting. The lubricants contain the additives like fatty oils and sulphurized fatty oils and chlorinated compounds.
3. The reduction in friction is only when _________ of the oil film is __________ than that of the metal.
a) shear strength, more
b) shear strain, less
c) shear strain, more
d) shear strength, less
Answer: d
Clarification: The friction in friction is only when shear strength of the oil film must be less than the metal. This will reduce the electricity consumption.
4. The friction is needed to be reduced because _________
a) will increase the load
b) will increase the consumption electricity
c) it will be reducing the excess heat generation
d) will increase the excess the heat generation
Answer: c
Clarification: The friction is needed to be reduced because it will be reducing the excess heat generation which will improve the machine life period.
5. Oil emulsions are the most effective lubricants in _________
a) heavy cuttings
b) light cutting
c) engines
d) gears
Answer: b
Clarification: Oil emulsions are the most effective lubricants in light cuttings. The emulsions have less lubricating effects than that of cutting oils but cutting oils are good as cooling media.
6. The lubricant in internal combustion is exposed to _________
a) high pressure
b) low pressure
c) low temperature
d) high temperature
Answer: d
Clarification: The lubricant in internal combustion is exposed to high temperatures. So, the lubricant must have the high thermal stability.
7. The lubricants that are suitable for internal combustion engines must have ______ viscosity index.
a) high
b) low
c) no
d) minimum
Answer: a
Clarification: The lubricant that is used in internal combustion engines must have the high viscosity index because it is exposed very high temperatures that are produced by the engines.
8. In gears, the lubricants are exposed to _______
a) high temperature
b) high pressure
c) low temperature
d) low pressure
Answer: b
Clarification: In gears, there will be high pressure so, the lubricants are exposed to high pressure and in the high temperatures will be in internal combustion engines.
9. The lubricants for gears must possess _________
a) less oiliness
b) effected by centrifugal force
c) resistance to oxygen
d) low load carrying capacity
Answer: c
Clarification: For gears, the lubricants must have the resistance to oxygen. The oxygen reacting with metal will form rust and makes the machine damages. so; the lubricants must have resistance towards the oxygen.
10. For, delicate instruments the suitable lubricants are _________
a) light cutting oil
b) sunflower oil
c) heavy cutting oil
d) thin vegetable oil