Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. White Phosphorous is represented by which among the following symbols?
[A] P1
[B] P2
[C] P3
[D] P4
Show Answer
Correct Answer: D [P4]
Notes:
The most important form of elemental phosphorus from the perspective of applications and chemical literature is white phosphorus. It consists of tetrahedral P4 molecules, in which each atom is bound to the other three atoms by a single bond. This P4 tetrahedron is also present in liquid and gaseous phosphorus up to the temperature of 800 °C when it starts decomposing to P2 molecules
2. What is Carbamide?
[A] A Pesticide
[B] A Fertilizer
[C] A Textile Dye
[D] An Explosive
Show Answer
Correct Answer: B [A Fertilizer]
Notes:
Carbamide is another name of Urea, an organic compound with chemical formula CO(NH2)2. This name indicates that Urea is an amide in which two –NH2 groups are joined by a carbonyl (C=O) functional group.
3. Ground Level Ozone is formed due to reaction between:
[A] VOCs, Oxides of Nitrogen & Sunlight
[B] VOCs, Sulphur dioxide & Sunlight
[C] Ozone, Sulphur dioxide & Oxides of Nitrogen
[D] Ozone, Oxides of Nitrogen & Sunlight
Show Answer
Correct Answer: A [VOCs, Oxides of Nitrogen & Sunlight]
Notes:
Ground Level Ozone results from photochemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs) in the presence of sunlight.
4. Which of the following represents the general formula for alkanes?
[A] CnH2n
[B] CnH2n-2
[C] CnH2n+2
[D] CnHn
Show Answer
Correct Answer: C [CnH2n+2]
Notes:
Alkanes are saturated open chain hydrocarbons containing carbon – carbon single bonds.
5. Which of the following compounds is manufactured using the Contact Process?
[A] Sulphuric Acid
[B] Nitric Acid
[C] Hydrochloric Acid
[D] Benzene
Show Answer
Correct Answer: A [Sulphuric Acid]
Notes:
The Contact Process is a method primarily used for preparing sulphuric acid on a large scale. It involves the oxidation of sulfur dioxide to sulfur trioxide in presence of a catalyst such as vanadium pentoxide. The subsequent hydration of sulfur trioxide produces sulphuric acid. The Contact Process allows the production of high concentrations of sulphuric acid under economically feasible conditions.
6. Which of the following is an example of colloidal solution?
[A] Milk
[B] Fog
[C] Smoke
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Milk, Fog, Smoke, Cheese, Clouds, Mist, Shaving cream, Butter, Jelly etc. are some of the examples of colloidal solution.
7. Which of the following is a correct statement about minerals and ores?
[A] All minerals are ores
[B] All ores are minerals
[C] Minerals are the native form in which various metals exist
[D] Ores are usually used to extract metals economically
Show Answer
Correct Answer: A [All minerals are ores]
Notes:
All ores are minerals but all minerals are not ores. Minerals are the native form in which various metals exist and ores are those minerals which are used to extract metals economically.
8. Which of the following methods is most suitable for ore concentration if the ore is soluble in some suitable solvent?
[A] Hydraulic Washing
[B] Magnetic Separation
[C] Froath floatation
[D] Leaching
Show Answer
Correct Answer: D [Leaching]
Notes:
Leaching is used for ore concentration if the ore is soluble in some suitable solvent. For example: Leaching of alumina from bauxite using conc. NaOH.
9. What is the sum of powers of the concentration of the reactants called as?
[A] Order of reaction
[B] Stage of reaction
[C] Zone of reaction
[D] None of the above
Show Answer
Correct Answer: A [Order of reaction]
Notes:
The sum of powers of the concentration of the reactants in the rate law expression is known as the order of that chemical reaction.
10. Which of the following elements is identified by the 7th group and 4th period of the modern periodic table?
[A] Copper
[B] Iron
[C] Manganese
[D] Chromium
Show Answer
Correct Answer: C [Manganese]
Notes:
Manganese is placed in the 7th group and 4th period of the modern periodic table. Its Atomic number is 25 and is placed group VII A.
