Chemistry - Study Mode
[#516] Most poisonous pollutant in water is
Correct Answer
(C) Arsenic
Explanation
Solution: Most poisonous pollutant in water is arsenic.
[#517] Which of the following can be found as pollutants in the drinking water in some parts of India? Select the correct answer using the code given below. (A) Arsenic (B) Sorbitol (C) Fluoride (D) Formaldehyde (E) Uranium
Correct Answer
(C) A, C and E
Explanation
Solution: Recent research has shown that India’s groundwater faces the problem of presence of uranium, arsenic, and heavy metals in ground water used for drinking. Sorbitol (used as artificial sweetener) and Formaldehyde (used in coating, etc) are not famous as water pollutants.
[#518] Smog is
Correct Answer
(B) A combination of smoke and fog
Explanation
Solution: Smog is air pollution that reduces visibility. The term "smog" was first used in the early 1900s to describe a mix of smoke and fog. The smoke usually came from burning coal. Smog was common in industrial areas, and remains a familiar sight in cities today. Today, most of the smog we see is photochemical smog.
[#519] When a spoon is to be electroplated with nickel the spoon is
Correct Answer
(C) Made cathode and a pure nickel red, the anode
Explanation
Solution: Electroplating is the deposition by electrolysis of a coating of metal upon a conducting surface. The simplest system makes the object to be plated the negative electrode (cathode) or plate in a galvanic couple. Thus a spoon or other object may be connected by a wire to a plate of nickel. The process that occurs on the spoon is called reduction and, therefore, the spoon is also referred to as a cathode.
[#520] Conversion of chemical energy into electrical energy occurs in
Correct Answer
(C) A battery
Explanation
Solution: The chemical energy in food is converted by the body into mechanical energy and heat. The chemical energy in coal is converted into electrical energy at a power plant. The chemical energy in a battery can also supply electrical power by means of electrolysis.