Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. Which among the following is the correct set of chemical formulae of Chile Saltpetre, Saltpetre and Quick Lime?
[A] KNO3, NaNO3, CaO
[B] NaNO3, KNO3, Ca(OH)2
[C] Na(OH)2, KOH, CaO
[D] NaNO3, KNO3, CaO
Show Answer
Correct Answer: D [NaNO3, KNO3, CaO]
Notes:
Saltpetre, also spelled Saltpeter, also called Nitre, or Niter, any of three naturally occurring nitrates, distinguished as (1) ordinary saltpetre, or potassium nitrate, KNO3; (2) Chile saltpetre, cubic nitre, or sodium nitrate, NaNO3; and (3) lime saltpetre, wall saltpetre, or calcium nitrate, Ca(NO3)2.
Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound.
2. Which among the following acids is abundant in Grapes, Bananas and Tamarind?
[A] Lactic Acid
[B] Oxalic Acid
[C] Salicylic Acid
[D] Tartaric Acid
Show Answer
Correct Answer: D [Tartaric Acid ]
Notes:
Tartaric acid occurs naturally in many fruits such as grapes, bananas, tamarinds, and citrus. Its salt, potassium bitartrate, commonly known as cream of tartar, develops naturally in the process of winemaking. It is commonly mixed with sodium bicarbonate and is sold as baking powder used as a leavening agent in food preparation. The acid itself is added to foods as an antioxidant E334 and to impart its distinctive sour taste.
3. Which among the following gases is used in production of Vanaspati ghee from vegetable oils?
[A] Nitrogen (N2)
[B] Carbon Dioxide (CO2)
[C] Hydrogen (H2)
[D] Neon (Ne)
Show Answer
Correct Answer: C [Hydrogen (H2)]
Notes:
Hydrogen (H2) gas is utilized in the manufacture of Vanaspati ghee from vegetable oils. The process involves hydrogenation, a chemical reaction between molecular hydrogen (H2) and another compound or element. Hydrogenation of vegetable oils helps to convert them into a semisolid form that resembles ghee, often used as a cheaper alternative to butter or ghee in cooking.
4. Which among the following kinds of glass is used generally in making of the Bullet proof screens?
[A] Pyrex glass
[B] Jena glass
[C] Reinforced Glass
[D] Flint Glass
Show Answer
Correct Answer: C [Reinforced Glass]
Notes:
Reinforced Glass or Toughened glass or tempered glass is a kind of safety glass is used as s a component of bulletproof glass, for diving masks, and various types of plates and cookware.
5. Which of the following chemicals is also known as lachrymatory agent or lachrymator?
[A] Mustard Gas
[B] Tear gas
[C] Diborane
[D] Chlorine gas
Show Answer
Correct Answer: B [ Tear gas]
Notes:
Tear gas is also known as CS Gas. It acts as a lachrymatory agent. Tear gas irritate the mucous membrane of the eyes, nose, mouth and lungs, and causes tearing, coughing, burning and difficult breathing.
6. Which of the following laws states that the partial vapour pressure of each component of an ideal mixture of liquids is equal to the vapour pressure of the pure component multiplied by its mole fraction in the mixture?
[A] Raoult’s law
[B] Henry’s law
[C] Graham’s law
[D] Sievert’s law
Show Answer
Correct Answer: A [ Raoult’s law]
Notes:
Raoult’s law states that the partial vapour pressure of each component of an ideal mixture of liquids is equal to the vapour pressure of the pure component multiplied by its mole fraction in the mixture.
7. Which of the following is the use of washing soda?
[A] softening of water
[B] manufacture of glass
[C] manufacture of paints
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
It is used for softening of water, laundering, cleaning, manufacture of glass, soap, borax, paper, paints and textile It is also extensively used as laboratory reagent.
8. Water Gas is a mixture of?
[A] CO and H2
[B] CO and H2O
[C] CO2 and H2
[D] None of the Above
Show Answer
Correct Answer: A [CO and H2]
Notes:
The mixture of CO and H2 produced is known as water gas or synthesis gas.
9. Which of the following alpha-emitter is commonly used in smoke detectors?
[A] Bismuth – 209
[B] Amrecium-231
[C] Uranium-238
[D] Protactinium-231
Show Answer
Correct Answer: B [Amrecium-231]
Notes:
Americium-241 is an isotope of americium. It is the most common isotope of americium having a half-life of 432.2 years. It is radioactive and is commonly used in ionization type smoke detectors.
10. What is the octane number of iso-octane?
[A] 1
[B] 0
[C] 100
[D] 200
Show Answer
Correct Answer: C [100]
Notes:
Octane number, also known as octane rating, are based on a scale on which iso-octane is 100, which means minimal knock, and heptane is 0. The higher the octane number, the more compression required for fuel ignition.
