Q. 1
General Knowledge
Difficulty: Easy
(1 Mark)
The most abundant element in the earth’s crust is:
💡
Step-by-Step Explanation & Concept Rationale
Oxygen is the most abundant element in the Earth's crust by mass, accounting for approximately 46.6%.
Q. 2
General Knowledge
Difficulty: Easy
(1 Mark)
Which one of the following is a non-metallic mineral?
💡
Step-by-Step Explanation & Concept Rationale
Gypsum is a soft sulfate mineral; Manganese, Magnesium, and Bauxite are either metals or ores from which metals are extracted.
Q. 3
General Knowledge
Difficulty: Easy
(1 Mark)
Which... chemicals in automobile exhaust can cause cancer?
💡
Step-by-Step Explanation & Concept Rationale
PAHs are potent atmospheric pollutants and known carcinogens produced by the incomplete combustion of organic matter like fuel.
Q. 4
General Knowledge
Difficulty: Easy
(1 Mark)
Acid rain is caused by pollution of environment by:
💡
Step-by-Step Explanation & Concept Rationale
These gases react with water, oxygen, and other chemicals in the atmosphere to form sulfuric and nitric acids.
Q. 5
General Knowledge
Difficulty: Easy
(1 Mark)
Galvanised iron is iron coated with
💡
Step-by-Step Explanation & Concept Rationale
Galvanization is the process of applying a protective zinc coating to steel or iron to prevent rusting and corrosion.
Q. 6
General Knowledge
Difficulty: Easy
(1 Mark)
Sucrose on hydrolysis with dilute acids give:
💡
Step-by-Step Explanation & Concept Rationale
Sucrose is a disaccharide that breaks down into its constituent monosaccharides—glucose and fructose—during hydrolysis.
Q. 7
General Knowledge
Difficulty: Easy
(1 Mark)
Bagasse, a by-product of sugar manufacturing industry, is used for the production of:
💡
Step-by-Step Explanation & Concept Rationale
Bagasse is the dry pulpy fibrous residue that remains after sugarcane stalks are crushed, used extensively as a paper pulp source.
Q. 8
General Knowledge
Difficulty: Easy
(1 Mark)
Which of the following is the most stable element?
💡
Step-by-Step Explanation & Concept Rationale
Lead is the final, stable product of several radioactive decay chains, making it one of the most nuclear-stable heavy elements.
Q. 9
General Knowledge
Difficulty: Easy
(1 Mark)
Bauxite is:
💡
Step-by-Step Explanation & Concept Rationale
Bauxite is a naturally occurring heterogeneous sedimentary rock that serves as the principal ore for extracting aluminum. Chemically, its primary component consists of various aluminum hydroxide minerals (such as gibbsite, boehmite, and diaspore), which are collectively represented by the general formula for hydrated aluminum oxide.
Q. 10
General Knowledge
Difficulty: Easy
(1 Mark)
The group of metals Fe, Co, Ni may be best called as:
💡
Step-by-Step Explanation & Concept Rationale
Iron (Fe), Cobalt (Co), and Nickel (Ni) are located in the d-block of the periodic table and are classic transition metals.
Q. 11
General Knowledge
Difficulty: Easy
(1 Mark)
Aqua regia is concentrated HNO3 : concentrated HCl:
💡
Step-by-Step Explanation & Concept Rationale
Aqua regia (royal water) is a highly corrosive mixture made of one part nitric acid and three parts hydrochloric acid.
Q. 12
General Knowledge
Difficulty: Medium
(1 Mark)
Which... laws is explained by the statement that matter can neither be created nor destroyed?
💡
Step-by-Step Explanation & Concept Rationale
This fundamental principle states that the total mass of substances in a closed system remains constant during a chemical reaction.
Q. 13
General Knowledge
Difficulty: Easy
(1 Mark)
A lighted candle gets extinguished when covered with a tumbler because of:
💡
Step-by-Step Explanation & Concept Rationale
Combustion requires oxygen; once the oxygen inside the tumbler is consumed, the chemical reaction stops and the flame dies.
Q. 14
General Knowledge
Difficulty: Easy
(1 Mark)
What is the best explanation for hard water?
💡
Step-by-Step Explanation & Concept Rationale
Hard water is formed when water percolates through deposits of limestone, chalk, or gypsum, dissolving these minerals.
Q. 15
General Knowledge
Difficulty: Easy
(1 Mark)
Which of the following gases is used in fire extinguisher?
💡
Step-by-Step Explanation & Concept Rationale
CO2 is used because it is non-flammable and heavier than air, effectively smothering the fire by displacing oxygen.
Q. 16
General Knowledge
Difficulty: Easy
(1 Mark)
Excessive chlorination leads to pollution of water by producing:
💡
Step-by-Step Explanation & Concept Rationale
When chlorine gas (\(\text{Cl}_{2}\)) is dissolved in water, it undergoes a disproportionation reaction to form hydrochloric acid (\(\text{HCl}\)) and hypochlorous acid (\(\text{HOCl}\)). Excessive chlorination overproduces these acids, causing a steep drop in the water's pH (making it highly acidic and corrosive) and creating secondary pollutant byproducts.
Q. 17
General Knowledge
Difficulty: Easy
(1 Mark)
Which of the following is a chemical change?
💡
Step-by-Step Explanation & Concept Rationale
Rusting is an oxidation reaction that changes iron into a new chemical substance, iron oxide.
Q. 18
General Knowledge
Difficulty: Easy
(1 Mark)
Mixture of water and alcohol can be separated by:
💡
Step-by-Step Explanation & Concept Rationale
Distillation relies on the different boiling points of water (100∘C) and ethanol (78∘C) to separate them.
Q. 19
General Knowledge
Difficulty: Easy
(1 Mark)
Which of the following is used as a food preservative?
💡
Step-by-Step Explanation & Concept Rationale
Sodium benzoate is widely used to inhibit the growth of mold, yeast, and some bacteria in acidic food products.
Q. 20
General Knowledge
Difficulty: Easy
(1 Mark)
Which of the following is not a by-product of coal gas?
💡
Step-by-Step Explanation & Concept Rationale
Coke, coal tar, and ammonia are primary byproducts of coal carbonization; Cobalt is an elemental metal.
Q. 21
General Knowledge
Difficulty: Easy
(1 Mark)
Which of the following is a gaseous pollutant?
💡
Step-by-Step Explanation & Concept Rationale
Hydrogen chloride (HCl) is a colorless gas with a pungent odor that acts as an atmospheric pollutant in industrial areas.
Q. 22
General Knowledge
Difficulty: Easy
(1 Mark)
The best antiknock compound used in petrol to increase mileage is:
💡
Step-by-Step Explanation & Concept Rationale
TEL was widely used as a gasoline additive to reduce engine "knocking" by raising the octane rating.
Q. 23
General Knowledge
Difficulty: Easy
(1 Mark)
Liquefied petroleum gas consists of mainly:
💡
Step-by-Step Explanation & Concept Rationale
LPG is a flammable mixture of hydrocarbon gases, primarily containing propane and butane.
Q. 24
General Knowledge
Difficulty: Easy
(1 Mark)
Which of the following is not a chemical change?
💡
Step-by-Step Explanation & Concept Rationale
Boiling water is a physical change (change of state), whereas the others involve the creation of new chemical substances.
Q. 25
General Knowledge
Difficulty: Easy
(1 Mark)
None-stick kitchenware is coated with:
💡
Step-by-Step Explanation & Concept Rationale
Teflon (polytetrafluoroethylene) is used for its extremely low friction and non-reactive properties.
Study Stream Progress:
Showing 25 of 38 Questions (66%)
Jump to:
Ready to Test Your Retention & Speed?
Now that you have reviewed the study questions and rationales, test yourself in our interactive 1-by-1 practice engine or take the full official timed mock exam.