Chemistry - Study Mode
[#196] The metal chiefly used for galvanising iron is :
Correct Answer
(A) Zinc
Explanation
Solution: Galvanisation or galvanization (or galvanizing as it is most commonly called) is the process of applying a protective zinc coating to iron or steel, to prevent rusting. The most common method is hot dip galvanizing, in which steel sections are submerged in a bath of molten zinc.
[#197] The anode in a dry cell consists of
Correct Answer
(B) Zinc
Explanation
Solution: A standard dry cell comprises a zinc anode, usually in the form of a cylindrical pot, with a carbon cathode in the form of a central rod. The electrolyte is ammonium chloride in the form of a paste next to the zinc anode.
[#198] Cement is usually a mixture of :
Correct Answer
(A) Calcium silicate and calcium aluminate
Explanation
Solution: Portland cement is the most common type of cement in general use around the world because it is a basic ingredient of concrete, mortar, stucco and most nonspecialty grout. It usually originates from limestone. It is a fine powder produced by grinding Portland cement clinker (more than 90%), a limited amount of calcium sulfate (which controls the set time) and up to 5% minor constituents. Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates, the remainder consisting of aluminium- and iron-containing clinker phases and other compounds.
[#199] Sodium bicarbonate is commercially known as
Correct Answer
(B) Baking soda
Explanation
Solution: Baking Soda is Sodium bicarbonate or sodium hydrogen carbonate. It is primarily used in cooking (baking), as a leavening agent. It reacts with acidic components in batters, releasing carbon dioxide, which causes expansion of the batter and forms the characteristic texture and grain in pancakes, cakes, quick breads, soda bread, and other baked and fried foods.
[#200] Which of the following is the main nitrogenous waste in humans ?
Correct Answer
(C) Uric Acid
Explanation
Solution: The excretory system functions in ridding the body of nitrogenous (nitrogen-containing, discussed below) and other wastes. Nitrogenous wastes of animals are excreted in form of ammonia, urea, or uric acid. They are excreted in the urine. Because ammonia is so water-soluble, aquatic animals often can get rid of it just by diffusion into the surrounding water. That’s one reason why the water in your aquarium gets “bad” and needs to be changed, and why not changing the water could kill the fish. However, ammonia doesn’t readily go from body fluids into air, so terrestrial animals need other ways of getting rid of nitrogenous wastes.