Chemistry (Part-XIII)

Total Questions: 50

41. Which of the following is used as a preservative? [S.S.C. Online M.T.S. (T-I) 26.10.2021 (Shift-I) ]

(a) Sodium Palmitate
(b) Sodium Chloride
(c) Magnesium Silicate
(d) Dipropylene Glycol

Correct Answer: (b) Sodium Chloride

Solution:Sodium chloride (NaCl), commonly known as table salt, has been used as a food preservative for centuries. It works by drawing out moisture from food through osmosis, thereby inhibiting the growth of bacteria, yeasts, and molds that cause spoilage. This method is used in curing meats and fish, and preserving vegetables (e.g., pickles).

42. What do you understand by the term Espuma? [C.P.O. S.I. 6.06.2016 (Shift-I) ]

(a) foam
(b) soap
(c) salt
(d) calcium

Correct Answer: (a) foam

Solution: "Espuma" is a Spanish word that translates to "foam". In culinary arts, particularly molecular gastronomy, an espuma refers to a light, airy foam or froth created using a whipping siphon (also known as a cream whipper or espuma gun) and a gelling agent or stabilizer. These foams can be sweet or savory and are used to add texture and flavor to dishes.

43. Which of the following statement is incorrect? [C.P.O. S.I. 5.06.2016 (Shift-I) ]

(a) Polystyrene was discovered by Edward Simon in 1839.
(b) It is used for plastic and CD boxes.
(c) It is not degradable in nature.
(d) None of the given options.

Correct Answer: (d) None of the given options.

Solution:(a) Polystyrene was discovered by Edward Simon in 1839. This statement is correct. Edward Simon, a German apothecary, indeed isolated polystyrene from styrene resin in 1839.

(b) It is used for plastic and CD boxes. This statement is correct. Polystyrene (PS) is a versatile plastic used in many applications, including disposable cutlery, protective packaging (Styrofoam), and rigid items like CD jewel cases and plastic models.

(c) It is not degradable in nature. This statement is also largely correct in practical terms. Polystyrene is highly resistant to biodegradation and can persist in the environment for hundreds of years, contributing significantly to plastic pollution.

Since all the statements (a), (b), and (c) are correct, the incorrect statement is (d) None of the given options.

44. The compound used in prickly-heat powder to prevent excessive sweating is- [S.S.C. Online Graduate Level (T-I) 6.09.2016 (Shift-II) ]

(a) Boric acid
(b) Phosphoric acid
(c) Carbonic acid
(d) Sulphonic acid

Correct Answer: (a) Boric acid

Solution:Boric acid (

H₃ B O₃

) has mild antiseptic and astringent properties, which make it useful in topical applications. In prickly-heat powders, it helps to absorb moisture, reduce friction, and inhibit bacterial growth, thus preventing and soothing rashes caused by excessive sweating. While other ingredients like talc and starch are primary components for absorption, boric acid contributes to the therapeutic effect.

45. The pressure of a gas on reducing its volume at constant temperature is _____ . [S.S.C. Online Stenographer 13.09.2017 (Shift-I) ]

(a) first increases then decrease
(b) increases
(c) decreases.
(d) No change takes place.

Correct Answer: (b) increases

Solution:This describes Boyle's Law, which states that for a fixed amount of gas at constant temperature, the pressure and volume are inversely proportional. If you reduce the volume of a gas, the gas molecules have less space to move around, leading to more frequent collisions with the container walls, and thus an increase in pressure.
Mathematically,

P₁ V₁ = P V₂

46. What is the melting point of ice at the sea-level at normal atmospheric pressure and at 45 degree latitude? [S.S.C. Online M.T.S. (T-I) 26.10.2021 (Shift-I) ]

(a) 222.14K
(b) 273.16K
(c) 256.14K
(d) 245.18K

Correct Answer: (b) 273.16K

Solution:The melting point of ice at any point above sea level at normal atmospheric pressure is 0°C. Which will have a value of 273.16K on the Kelvin scale because 0°C = 273.16K

47. Substances which provide heat in the form of energy in the combustion process are called? [S.S.C. Online Stenographer 13.09.2017 (Shift-I) ]

(a) CNG
(b) Igniter
(c) Fuel
(d) Thermal

Correct Answer: (c) Fuel

Solution:A fuel is any material that can be made to react with other substances (typically oxygen) to release energy as heat or light through a process called combustion. Examples include wood, coal, natural gas, gasoline, and hydrogen.

CNG is a type of fuel (Compressed Natural Gas).
Igniter is a device that starts combustion.
Thermal relates to heat but isn't the substance itself.

48. The brand name Teflon represents which polymer? [S.S.C. Online CHSL (T-I) 31.01.2017 (Shift-III) ]

(a) Polystyrene
(b) Polypropylene
(c) Polytetrafluoroethylene
(d) Polyethylene Terephthalate

Correct Answer: (c) Polytetrafluoroethylene

Solution:Teflon is the brand name for Polytetrafluoroethylene (PTFE). PTFE is a synthetic fluoropolymer of tetrafluoroethylene. It is well-known for its non-stick properties (used in cookware) and its extremely low coefficient of friction, as well as its high resistance to heat and chemicals.

49. Limestone is a raw material used by which industry? [S.S.C. Online Graduate Level (T-I) 8.09.2016 (Shift-I) ]

(a) Aluminium
(b) Fertilizers
(c) Cement
(d) Petrochemicals

Correct Answer: (c) Cement

Solution:Limestone (

C a C O₃

) is a primary raw material in the cement industry. It is crushed, mixed with other materials like clay, and heated in a kiln to produce clinker, which is then ground to make cement. Cement is a crucial component of concrete.

50. Trinitrotoluene is- [S.S.C. Online Graduate Level (T-I) 2.09.2016 (Shift-I) ]

(a) used to melt metals
(b) used to fuse two metals
(c) used as an abrasive
(d) used as an explosive

Correct Answer: (d) used as an explosive

Solution:Trinitrotoluene (TNT) is a highly stable, powerful, and widely used explosive. It is a common benchmark for the destructive power of other explosives. Its chemical formula is C₇H₅N₃O₆.

« Previous 1 2 3 45