Q1. What is the process by which a substance changes directly from a solid to a gas without passing through the intermediate liquid phase?
a) Condensation
b) Evaporation
c) Sublimation
d) Deposition
Show Answer
Correct Answer: c) Sublimation
Explanation: Sublimation is the process in which a substance transitions directly from the solid phase to the gas phase without passing through the liquid phase. This phenomenon occurs when the vapor pressure of the solid exceeds the atmospheric pressure at a certain temperature. Sublimation is observed in various substances, including dry ice (solid carbon dioxide), iodine crystals, and certain volatile compounds. The reverse process, where a gas transitions directly to a solid without becoming a liquid, is known as deposition. Sublimation has practical applications in processes such as freeze-drying, purification of substances, and the formation of snowflakes and frost.
Q2. Which chemical element is represented by the symbol ‘Ne’ in the periodic table?
a) Neon
b) Nickel
c) Nitrogen
d) Sodium
Show Answer
Correct Answer: a) Neon
Explanation: Neon is a chemical element with the atomic number 10 and the symbol ‘Ne’ in the periodic table. It is a noble gas belonging to Group 18 (also known as Group 0 or Group VIII) and Period 2. Neon is colorless, odorless, and inert under standard conditions, making it useful in various applications, including lighting, advertising signs, and cryogenic refrigeration. Its name is derived from the Greek word ‘neos,’ meaning ‘new.’ Neon is most commonly associated with bright, orange-red glow discharge lamps and neon signs.
Q3. Which modern chemical process is used to convert natural gas or methane into liquid hydrocarbons?
a) Polymerization
b) Fermentation
c) Cracking
d) Fischer-Tropsch synthesis
Show Answer
Correct Answer: d) Fischer-Tropsch synthesis
Explanation: Fischer-Tropsch synthesis is a modern chemical process used to convert synthesis gas (syngas), derived from natural gas, coal, or biomass, into liquid hydrocarbons and other valuable products. The process involves a series of catalytic reactions that transform carbon monoxide (CO) and hydrogen (H2) into long-chain hydrocarbons, such as paraffins and olefins, which can be further processed into fuels and chemicals. Fischer-Tropsch synthesis is utilized in the production of synthetic fuels, lubricants, waxes, and specialty chemicals and plays a role in reducing dependence on petroleum-based resources.
Q4. What is the term for a substance that speeds up the rate of a chemical reaction without undergoing any permanent change itself?
a) Catalyst
b) Solvent
c) Reactant
d) Product
Show Answer
Correct Answer: a) Catalyst
Explanation: A catalyst is a substance that speeds up the rate of a chemical reaction by providing an alternative reaction pathway with lower activation energy, without undergoing any permanent change itself. Catalysts enable reactions to proceed at a faster rate and under milder conditions than would otherwise be possible. They are commonly used in various industrial processes, including petroleum refining, chemical synthesis, and environmental remediation. Catalysts can be homogeneous (present in the same phase as the reactants) or heterogeneous (present in a different phase) and play critical roles in enhancing efficiency, selectivity, and sustainability of chemical processes.
Q5. Which branch of chemistry deals with the study of carbon compounds, including hydrocarbons and their derivatives?
a) Organic chemistry
b) Inorganic chemistry
c) Physical chemistry
d) Analytical chemistry
Show Answer
Correct Answer: a) Organic chemistry
Explanation: Organic chemistry is the branch of chemistry that deals with the study of carbon compounds, including hydrocarbons and their derivatives. Organic compounds are characterized by the presence of carbon atoms bonded to hydrogen and other elements, such as oxygen, nitrogen, sulfur, and halogens. Organic chemistry encompasses the study of various classes of compounds, including alkanes, alkenes, alkynes, aromatics, alcohols, ethers, ketones, aldehydes, carboxylic acids, esters, and amines. It has applications in numerous fields, including pharmaceuticals, agrochemicals, polymers, materials science, and biochemistry.
Q6. Which chemical element is essential for all known forms of life and is a key component of biomolecules such as proteins, nucleic acids, and carbohydrates?
a) Phosphorus
b) Calcium
c) Carbon
d) Hydrogen
Show Answer
Correct Answer: c) Carbon
Explanation: Carbon is essential for all known forms of life and is a key component of biomolecules such as proteins, nucleic acids, carbohydrates, lipids, and vitamins. Carbon’s unique ability to form stable covalent bonds with other elements, including itself, allows for the vast diversity and complexity of organic compounds found in living organisms. Carbon atoms can form single, double, or triple bonds with other atoms, giving rise to a wide variety of molecular structures and functionalities. The carbon cycle, which involves the exchange of carbon between the atmosphere, biosphere, hydrosphere, and lithosphere, is crucial for regulating Earth’s climate and sustaining life on the planet.
Q7. Which chemical process involves the conversion of carbohydrates, such as glucose or starch, into ethanol and carbon dioxide by fermentation?
a) Combustion
b) Photosynthesis
c) Fermentation
d) Oxidation
Show Answer
Correct Answer: c) Fermentation
Explanation: Fermentation is a metabolic process that involves the conversion of carbohydrates, such as glucose or starch, into ethanol and carbon dioxide by microorganisms such as yeast and bacteria. During fermentation, microorganisms metabolize sugars anaerobically (in the absence of oxygen), producing ethanol and carbon dioxide as byproducts. Fermentation is utilized in various industrial processes, including the production of alcoholic beverages (e.g., beer, wine, and spirits), biofuels (e.g., ethanol), and fermented foods (e.g., yogurt, cheese, and sauerkraut). It is an ancient biotechnological process with significant economic, cultural, and nutritional importance.
Q8. Which chemical element is commonly used as a reducing agent in metallurgy and is essential for the production of steel?
a) Zinc
b) Copper
c) Iron
d) Carbon
Show Answer
Correct Answer: d) Carbon
Explanation: Carbon is commonly used as a reducing agent in metallurgy and is essential for the production of steel through the process of iron smelting in blast furnaces. During iron smelting, carbon reduces iron oxide (Fe2O3 or Fe3O4) to elemental iron (Fe) by reacting with oxygen to form carbon monoxide (CO) or carbon dioxide (CO2). This process, known as the blast furnace reaction, is a key step in the production of pig iron, which is further refined into steel. Carbon’s ability to remove oxygen from metal ores and form strong alloys with iron makes it indispensable in the steelmaking industry.
Q9. Which modern chemical process is used to convert crude oil or petroleum into various
petroleum products, such as gasoline, diesel, and jet fuel?
a) Polymerization
b) Cracking
c) Hydrogenation
d) Distillation
Show Answer
Correct Answer: b) Cracking
Explanation: Cracking is a modern chemical process used in the petroleum industry to break down large hydrocarbon molecules in crude oil into smaller, more valuable hydrocarbon products, such as gasoline, diesel, and jet fuel. This process involves the thermal or catalytic decomposition of long-chain hydrocarbons into shorter-chain hydrocarbons, along with the production of byproducts like alkenes and hydrogen gas. Cracking improves the yield of high-demand petroleum products, enhances their octane rating, and optimizes the composition of fuel blends. Various cracking methods, including thermal cracking, catalytic cracking, and hydrocracking, are employed in petroleum refining to meet market demands and regulatory specifications.
Q10. Which modern chemical process is used to convert renewable biomass, such as agricultural residues and forestry waste, into biofuels and biochemicals?
a) Fermentation
b) Cracking
c) Pyrolysis
d) Electrolysis
Show Answer
Correct Answer: c) Pyrolysis
Explanation: Pyrolysis is a modern chemical process used to convert renewable biomass, such as agricultural residues, forestry waste, and energy crops, into biofuels, biochemicals, and bioproducts. This thermochemical conversion process involves heating biomass in the absence of oxygen (anaerobic conditions) to break down complex organic molecules into simpler compounds, such as bio-oil, biochar, and syngas (synthesis gas). Pyrolysis offers several advantages, including the production of renewable fuels and chemicals, mitigation of waste disposal issues, and potential carbon sequestration through biochar utilization. It represents a promising pathway for sustainable energy production and resource utilization in the transition to a bio-based economy.