61. A packet of potato chips is flushed with a gas to prevent the chips from turning rancid. Which gas is most commonly used for this purpose?
(a) Oxygen
(b) Chlorine
(c) Hydrogen
(d) Nitrogen
Answer:
(d) Nitrogen
Explanation:
Nitrogen gas is inert and flushes out oxygen to prevent oxidation of fats and oils in the chips, keeping them fresh and preventing rancidity.
62. What is the pH range of the human body for its proper functioning?
(a) 2.0 to 3.5
(b) 7.0 to 7.8
(c) 9.0 to 10.5
(d) 6.0 to 7.0
Answer:
(b) 7.0 to 7.8
Explanation:
The human body generally functions strictly within a slightly alkaline pH range of 7.0 to 7.8.
63. An alloy is a/an:
(a) Element
(b) Compound
(c) Homogeneous mixture
(d) Heterogeneous mixture
Answer:
(c) Homogeneous mixture
Explanation:
An alloy is defined as a homogeneous mixture of two or more metals, or a metal and a non-metal.
64. The reaction between ethanol and ethanoic acid in the presence of an acid catalyst to form a sweet-smelling substance is called:
(a) Saponification
(b) Esterification
(c) Hydrogenation
(d) Fermentation
Answer:
(b) Esterification
Explanation:
When an alcohol (like ethanol) reacts with a carboxylic acid (like ethanoic acid) in the presence of an acid catalyst, it forms a sweet-smelling ester. This process is called esterification.
65. Ethanoic acid is commonly called “glacial acetic acid” because:
(a) It freezes to form ice-like crystals in cold climates
(b) It is used to preserve ice
(c) It is found in glaciers
(d) It reacts violently with water like ice
Answer:
(a) It freezes to form ice-like crystals in cold climates
Explanation:
Pure ethanoic acid has a melting point of , so it frequently freezes into solid, ice-like crystals during winter in cold climates, earning the name “glacial acetic acid”.
