This set of Applied Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Lubricants General Questions”.
1. The lowest temperature at which the oils gives enough vapour.
a) Pour point
b) Cloud point
c) Flash point
d) Fire point
Explanation: The lowest temperature at which the oil gives the enough vapour is flash point. Cloud point is the temperature expressed in multiples of 1oC at which the haze of the wax crystal appears when the oil is cooled under prescribed conditions.
2. The fire point is the lowest temperature at which the vapour of oil burns continuously for at least ________ when a small flame is brought near to it.
a) 1 Second
b) 2 Seconds
c) 4 Seconds
d) 5 Seconds
Explanation: The fire point is the lowest temperature at which the vapour of oil burns continuously for at least 5seconds when a small flame is brought near to it. The flash point means the at lowest temperature the oil gives enough vapour and flashes out is called flash point.
3. The fire point of an oil is about ________ higher than the flash point.
Explanation: The fire is point of an oil is usually greater than the flash point of it. The fire point of oil is about 5-40oC higher than the flash point.
4. The lubricating oil is volatilises then the formed vapour _____
a) Must be less
b) Must be high
c) Non- inflammable
Explanation: Many times the lubricant in use must face the high temperatures. The good lubricating oil must not volatilises even if volatilises its vapours should not catch the fire.
5. Pensky -Marten’s apparatus is used to find out the ________
a) Cloud point
b) Pour point
c) Flash point
d) Fire point
Explanation: Pensky -Marten’s apparatus is used to find out the flash point of the lubricating oil at the temperature in between the 80-3700C.
6. Oil cup in Pensky-marten’s apparatus is made with __________
Explanation: Oil cup in Pensky-marten’s apparatus is made with the brass. Brass does not undergo rusting. The oil cup is made with metals that do not undergo rusting. Iron, copper and steel undergo rusting and having equivalent conductivity.
7. The location of the cup in air bath can be known using __________
d) Pilot burner
Explanation: The location of the cup in air bath can be known using the flange. The cup is supported by a flange over heating vessel such a way that there is clearance between them.
8. Flame exposure device is connected with _______
c) Pilot burner
d) Oil cup
Explanation: Flame exposure device is connected with shutter. When the shutter is moved to open the opening in it, the flame exposure devices are dipped in the opening.
9. Transformer oils must have _________
a) More oiliness
b) More viscosity
c) Good dielectric strength
d) Low dielectric strength
Explanation: The transformer oils must be filtered and dried properly before they put into use because any moisture in them may damage the device or leads to short circuits. The dielectric oils must have good dielectric strength.
10. For refrigerator system, the oils with the low viscosity, high cloud point and low pour point are used.
Explanation: For refrigerator system, the oils with the low viscosity, low cloud point and low pour point are used. Mostly, these characteristics are seen in naphthalene-base oils. So, they are used for these purposes.
11. The maximum pour-point requirements for refrigerator system are about ________ for lightest grade.
Explanation: The maximum pour point requirements for refrigerator system is about -40oF for lightest grade. For the heaviest grade the maximum pour point is about -13oF.
Sanfoundry Global Education & Learning Series – Applied Chemistry.
To practice all areas of Applied Chemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.