Chemical Plant Utilities Quiz - Insight into Chemical Engineering

CPU Quiz – 1

Q 1: Water that forms scum with soap is called

A) hard water

B) soft water

C) distilled water

D) non distilled water

Answer is A)

Explanation: Hard water reacts with the soap solution and forms a white curdy insoluble precipitate known as scum.

Q 2: The hardness which can be removed by boiling is called

A) permanent hardness

B) temporary hardness

C) stiffness

D) toughness

Answer is B)

Explanation: Soluble salts (calcium and magnesium bicarbonates) cause temporary hardness. When heated, these soluble salts decompose and precipitate out as insoluble salts.

${Mg\left({\mathrm{HCO}}_3\right)}_2\;\xrightarrow{heating}{\mathrm{MgCO}}_3\;+H_2O+{\mathrm{CO}}_2$

${Ca\left({\mathrm{HCO}}_3\right)}_2\;\xrightarrow{heating}{\mathrm{CaCO}}_3\;+H_2O+{\mathrm{CO}}_2$

Q 3: ________ is the removal of calcium, magnesium, and certain other metal cations in hard water.

A) Disinfection

B) Sedimentation

C) Softening

D) Cleaning

Answer is C)

Explanation: The removal of calcium, magnesium and other metal cations from hard water is known as water softening.

Q 4: Which of these methods does not remove hardness?

A) Reverse osmosis

B) Ion exchange resins

C) Chelating agents

D) Sedimentation

Answer is D)

Explanation: Only suspended solids can be removed using sedimentation.

Q 5: A device used to measure humidity is called a

A) Psychrometer

B) Hygrometer

C) Both

Answer is C)

Explanation: A psychrometer measures humidity by taking temperature readings from both wet-bulb and dry-bulb.

**Psychrometer** (Image Ref: Show location)

A hygrometer is an instrument that measures the amount of water vapor in the air, soil, or confined spaces.

**Hygrometer** (Image Ref: Show location)

Q 6: Amount of water vapor in the air is regarded as.

A) water vapor

B) humidity

C) mildness

D) pressure

Answer is B)

Explanation: The amount of water vapor present in the air is defined as humidity.

Q 7: Humidity is the result of

A) Evaporation

B) Transpiration

C) Presence of heat

D) Presence of moisture content in the air

Answer is D)

Explanation: The amount of water vapor present in the air is defined as humidity.

Q 8: The orange color cannot be used on the surface of the cast which is not finished and left.

A) True

B) False

Answer is B)

Explanation: None of the casting surfaces are colored green. Cast surfaces that have yet to be machined are colored red.

Q 9: Both temporary and permanent hardness of water can be removed by

A) boiling

B) distillation

C) filtration

D) filtration

Answer is B)

Explanation: For removing temporary hardness, boiling and filtration can be used. Decantation is the separation of insoluble solid particles from a liquid or the separation of two immiscible liquids with different densities. Distillation can be used to remove both temporary and permanent water hardness.

Q 10: Which of the following substances are commonly used in a filter?

A) Charcoal

B) Sand

C) Both (A) and (B)

D) Aluminum chloride

Answer is C)

Explanation: Both charcoal and sand are used in filters due to their porous nature.

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CPU Quiz – 1

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