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 oxides cause the Acid rain?
[A] Carbon monoxide and carbon dioxide
[B] Nitrous oxide and sulphur dioxide
[C] Carbon dioxide and nitrous oxide
[D] Sulphur dioxide and carbon monoxide
Show Answer
Correct Answer: B [Nitrous oxide and sulphur dioxide ]
Notes:
Acid rain is caused by nitrous oxides (NOx) and sulfur dioxide (SO2) emissions, which react with water molecules in the atmosphere to form nitric and sulfuric acids. These acids then fall to the ground in rain, snow, fog, or dust particles.
2. What is the electrical state of a molecule, considered the smallest part of matter retaining the properties of the original matter?
[A] Positive
[B] Negative
[C] Either positive or negative
[D] Neutral
Show Answer
Correct Answer: D [Neutral]
Notes:
A molecule represents the smallest portion of a substance that retains the characteristics of the substance. It’s electrically neutral because it’s made up of atoms that bond together, sharing or exchanging electrons to achieve stability. This process balances out the electrical charges of the protons and electrons, rendering the molecule as a whole electrically neutral.
3. Galvanizing is a metallurgical process that is used to coat steel or iron with which of the following?
[A] Zinc
[B] Lead
[C] Chromium
[D] Copper
Show Answer
Correct Answer: A [Zinc]
Notes:
Galvanisation is a method of protecting steel and iron from rusting by coating them with a thin layer of zinc
4. The atomic weight of Chlorine is 35. It consists of _______?
[A] 17 Protons + 18 Neutrons
[B] 17 Neutrons + 18 protons
[C] 17 Neutrons + 17 Protons + 1 electron
[D] None of the above
Show Answer
Correct Answer: A [17 Protons + 18 Neutrons]
Notes:
Chlorine has an atomic number of 17, meaning it has 17 protons. Its atomic weight is approximately 35, which indicates it typically has 18 neutrons (35 – 17 = 18). Therefore, the correct composition is 17 protons and 18 neutrons. Chlorine is a halogen and exists primarily as two stable isotopes: Chlorine-35 and Chlorine-37.
5. The chemical oxygen demand COD test is commonly used to measure which of the following?
[A] amount of organic compounds in water
[B] amount of oxygen in water
[C] amount of oxygen in a chemical
[D] amount of oxygen used in a oxygenation process
Show Answer
Correct Answer: A [amount of organic compounds in water]
Notes:
chemical oxygen demand is a measure of water quality and is amount of organic pollutants found in surface water. Potassium permanganate has been used for many years to measure COD
6. If a baby diaper is subjected to different solutions, which of the following will it absorb the maximum quantity of?
[A] Distilled Water
[B] Drinking Water
[C] Hard Water
[D] Urine
Show Answer
Correct Answer: A [Distilled Water]
Notes:
A baby diaper can absorb the maximum quantity of distilled water as it lacks impurities such as minerals and ions that are present in other type of water. The absorbent materials in diapers, often polymers called sodium polyacrylate, can hold up to 30 times their weight in distilled water, making them highly efficient.
7. Which of the following is NOT correct about Alkynes?
[A] They contain at least two triple bond between two carbon atoms
[B] The number of hydrogen atoms is less in alkynes as compared to alkenes
[C] The general formula of Alkynes is CnH2n–2
[D] All are correct
Show Answer
Correct Answer: A [They contain at least two triple bond between two carbon atoms]
Notes:
Alkynes contain at least one triple bond between two carbon atoms. The number of hydrogen atoms is less in alkynes as compared to alkenes or alkanes. Their general formula is CnH2n–2.
8. Which of the following elements have a compound named as Hydrogen peroxide?
[A] Hydrogen, Carbon and Oxygen
[B] Hydrogen only
[C] Hydrogen and Oxygen
[D] Hydrogen, Oxygen and Potassium
Show Answer
Correct Answer: C [Hydrogen and Oxygen]
Notes:
Hydrogen peroxide is a compound of Hydrogen and Oxygen.
9. Which of the following metal is the main constituent in Pewter alloy?
[A] Lead
[B] Zinc
[C] Tin
[D] Iron
Show Answer
Correct Answer: C [Tin]
Notes:
The term pewter covers a variety of alloys consisting primarily of tin. It is composed of 85–99% tin, mixed with copper, antimony, bismuth, silver or lead..
10. Which of the following defines the solubility of a solution?
[A] amount of the solvent present in the saturated solution
[B] amount of the solute present in the saturated solution
[C] amount of the solute per amount of solute in the solution
[D] difference of amount of solvent and the amount of solute
Show Answer
Correct Answer: B [amount of the solute present in the saturated solution]
Notes:
The amount of the solute present in the saturated solution at a given temperature is called its solubility.
