REFRIGERANTS (R & AC)

Freon group of refrigerants are

• Nontoxic and non-inflammable

• Toxic

• Inflammable

• Non-inflammable and toxic

The boiling point of ammonia is

• -10.5°C

• -77.7°C

• -33.3°C

• -30°C

The refrigerant widely used in domestic refrigerator is

• Carbon dioxide

• Sulphur dioxide

• R-12

• Ammonia

The vapour pressure of refrigerant should be

• Equal to atmospheric pressure

• Lower than atmospheric pressure

• Higher than atmospheric pressure

• Could be anything

The leaks in a refrigeration system using Freon are detected by

• Sulphur sticks which on detection gives white smoke

• Smelling

• Using reagents

• Halide torch which on detection produces greenish flame lighting

Which of the following refrigerant has the maximum ozone depletion potential in the stratosphere?

• Ammonia

• Sulphur dioxide

• Fluorine

• Carbon dioxide

Pick up the wrong statement. A refrigerant should have

• Tow specific heat of liquid

• Higher critical temperature

• High boiling point

• High latent heat of vaporisation

Which of the following statement is correct for ammonia as a refrigerant?

• It reacts with copper and its alloys

• All of these

• It is toxic to mucous membranes

• It requires large displacement per TR compared to fluoro carbons.

Freon group of refrigerants are

• Toxic

• Non-inflammable and toxic

• Inflammable

• Nontoxic and non-inflammable

Which of the following is not a desirable property of a refrigerant?

• Large latent heat

• High miscibility with oil

• Good electrical conductor

• Low boiling point