GATE Mechanical Engineering Question Papers with Answers 2023-2024 - 2

Question: 6

Temporary hardness in water is caused by salts like

(A) carbonates

(B) chlorides

(C) nitrates

(D) sulphates

Question: 7

Ultra-violet rays are used for the treatment of water known as

(A) filtration

(B) aeration

(C) disinfection

(D) dechlorination

Question: 8

The gas from sludge digestion tank is mainly composed of

(A) methane

(B) hydrogen sulphide

(C) carbon dioxide

(D) nitrogen

Question: 9

A blue smoke from a diesel engine indicates presence of

(A) unburnt oil

(B) carbon monoxide

(C) carbon dioxide

(D) nitrous oxide

Question: 10

For removal of temporary hardness of water

(A) lime is added with water

(B) alum is added to water

(C) water is flush

(D) water is boiled