Chemistry (Part-XIV)

Total Questions: 50

41. Phosphorus and nitrogen are examples of which types of impurities in sewage? [S.S.C. Online MTS (T-I) 20.09.2017 (Shift-II) ]

(a) Organic
(b) Inorganic
(c) Nutrients
(d) None of these

Correct Answer: (c) Nutrients

Solution:Nitrogen and phosphorous are essential basic nutrients for plants and animals, which are naturally present in the soil, air, and water. But at present, due to the increase in human activities, more quantity of them has started to be included in Sewage water, due to which these elements have taken the form of impurities, while they are nutrients.

42. The mineral Carnotite is an important source of: [S.S.C. Online MTS (T-I) 22.10.2021 (Shift-I) ]

(a) copper
(b) zinc
(c) iron
(d) uranium

Correct Answer: (d) uranium

Solution:Carnotite is a yellowish, radioactive mineral that is a hydrated potassium uranyl vanadate. It is a significant ore of uranium and also contains vanadium. It is found in sedimentary rocks in various parts of the world.

43. Which of the following gases is used in electric bulbs? [S.S.C. Online M.T.S. (T-I) 13.10.2021 (Shift-III) ]

(a) Hydrogen
(b) Halogen
(c) Nitrogen
(d) Carbon dioxide

Correct Answer: (c) Nitrogen

Solution:Incandescent electric bulbs (the traditional filament bulbs) are filled with inert gases like nitrogen or argon. These inert gases prevent the rapid evaporation of the tungsten filament, which would otherwise burn out quickly in the presence of oxygen. This significantly extends the bulb's lifespan. Nitrogen is often used alone or in a mixture with argon.

44. When dried raisins are placed in a concentrated salt solution, they ______ . [S.S.C. Online M.T.S. (T-I) 11.10.2021 (Shift-II) ]

(a) shrink
(b) swell
(c) first shrink and then swell
(d) remain the same size

Correct Answer: (a) shrink

Solution:When dried raisins are placed in a concentrated salt solution, they shrink in the solution due to exosmosis.

45. Which chemical reaction takes place during the cooking of meat? [S.S.C. Online C.H.S.L. (T-I) 15.04.2021 (Shift-II) ]

(a) The Finkelstein reaction
(b) The Maillard reaction
(c) The Swartz reaction
(d) The Gattermann reaction

Correct Answer: (b) The Maillard reaction

Solution:The Maillard reaction is a complex series of chemical reactions between amino acids (from proteins) and reducing sugars that gives browned food its distinctive flavor and color. It's responsible for the delicious browning and savory flavors in cooked meat (like steak, roasts), toasted bread, roasted coffee, and many other cooked foods. It occurs at temperatures above 140°C (280°F).

46. What is the total charge of an electric dipole? [S.S.C. Online C.H.S.L. (T-I) 11.08.2021 (Shift-I) ]

(a) +1
(b) -10
(c) 0
(d) 10

Correct Answer: (c) 0

Solution:An electric dipole is defined as two equal and opposite charges +q and -q, which are located at a fixed distance. These charges have the same magnitude, while the nature is opposite. Therefore, due to the equal and opposite nature of charges on the electric dipole, its total charge is zero.

47. Rain is liquid _____ . [S.S.C. Online C.H.S.L. (T-I) 12.08.2021 (Shift-I) ]

(a) decantation
(b) sedimentation
(c) precipitation
(d) condensation

Correct Answer: (c) precipitation

Solution:In meteorology, precipitation refers to any form of water that falls from the atmosphere to the Earth's surface. This includes rain, snow, sleet, hail, and drizzle. Rain is specifically liquid precipitation.

48. Onions produce the chemical irritant known as syn-propanethial-S-oxide; this stimulates the eyes ____ glands which release tears. [S.S.C. Online C.H.S.L. (T-I) 09.08.2021 (Shift-II) ]

(a) submandibular
(b) sublingual
(c) lachrymal
(d) parotid

Correct Answer: (c) lachrymal

Solution:On cutting an onion, intense burning starts in the eyes. This is due to the syn-Propanethial-S-oxide gaseous compound present in onion juice, which produces sulfenic acid. This gas reacts with the water of the eye and is immediately converted into sulfuric acid, which causes irritation in the eye. This compound is a lachrymatory agent i.e. it is a lacrimal agent.

49. When we cut an onion, the synthase enzyme converts the amino acid sulfoxides of the onion into which acid? [S.S.C. Online Graduate Level (T-I) 3.03.2020 (Shift-II) ]

(a) Sulfenic acid
(b) Nitric acid
(c) Sulphuric acid
(d) Citric acid

Correct Answer: (a) Sulfenic acid

Solution:When an onion is cut, cells are ruptured, releasing enzymes (specifically alliinase or lachrymatory factor synthase). These enzymes act on sulfur-containing amino acid sulfoxides (like isoalliin) naturally present in the onion. The initial product of this enzymatic reaction is sulfenic acid. Sulfenic acid is unstable and rapidly rearranges to form the lachrymatory factor (syn-propanethial-S-oxide), which causes the tears.

50. When we cut an onion, the vegetable emits an odour and our eyes tear up. Which of the following compounds is responsible for the tears and odour resulting from freshly cut onions? [S.S.C. Online Graduate Level (T-I) 18.08.2021 (Shift-III) ]

(a) Sulphuric acid
(b) Acetic acid
(c) Citric acid
(d) Ascorbic acid

Correct Answer: (a) Sulphuric acid

« Previous 1 2 3 45