Here are some multiple-choice questions (MCQs) with answers for Class 11 Chemistry Chapter 1, “Some Basic Concepts of Chemistry.” These questions are aligned with the CBSE board curriculum and cover topics from the latest Class 11 chemistry syllabus. By going through these MCQs, you can easily brush up on the concepts discussed in the chapter and get ready for your Class 11 Annual exams, along with other entrance exams like NEET and JEE.
Class 11 Some Basic Concepts of Chemistry MCQs
Question: The branch of chemistry that deals with the quantitative relationships between the reactants and products in chemical reactions is called:
A) Analytical chemistry
B) Physical chemistry
C) Organic chemistry
D) Inorganic chemistry
Answer: B) Physical chemistry
Question: Which of the following is NOT a basic unit of measurement in the International System of Units (SI)?
A) Meter
B) Gram
C) Kelvin
D) Pound
Answer: D) Pound
Question: The SI unit for temperature is:
A) Fahrenheit
B) Celsius
C) Kelvin
D) Rankine
Answer: C) Kelvin
Question: What is the SI unit of amount of substance?
A) Mole
B) Gram
C) Liter
D) Meter
Answer: A) Mole
Question: The number of significant figures in the measurement 0.00345 is:
A) 2
B) 3
C) 4
D) 5
Answer: C) 4
Question: Avogadro’s number is:
A) 6.022 × 10^23
B) 1.602 × 10^-19
C) 9.81 m/s^2
D) 3.00 × 10^8 m/s
Answer: A) 6.022 × 10^23
Question: The formula mass of a compound is the sum of the atomic masses of all atoms in a formula unit of the compound, expressed in:
A) Grams
B) Milligrams
C) Grams per mole
D) Kilograms
Answer: C) Grams per mole
Question: Which of the following is NOT a fundamental chemical property?
A) Melting point
B) Boiling point
C) Density
D) Reactivity
Answer: C) Density
Question: The mass of 1 mole of a substance is called its:
A) Molar mass
B) Atomic mass
C) Molecular weight
D) Formula mass
Answer: A) Molar mass
Question: The molar mass of water (H2O) is:
A) 16 g/mol
B) 18 g/mol
C) 20 g/mol
D) 22 g/mol
Answer: B) 18 g/mol
Question: Which of the following statements is TRUE about empirical formula?
A) It shows the actual number of atoms of each element in a molecule.
B) It is based on the molecular formula.
C) It represents the simplest whole-number ratio of atoms in a compound.
D) It is always the same as the molecular formula.
Answer: C) It represents the simplest whole-number ratio of atoms in a compound.
Question: The molecular formula of a compound is:
A) Always the same as its empirical formula
B) Always smaller than its empirical formula
C) Always larger than its empirical formula
D) Sometimes the same as its empirical formula
Answer: D) Sometimes the same as its empirical formula
Question: Which of the following is NOT a type of chemical reaction?
A) Synthesis
B) Decomposition
C) Fusion
D) Combustion
Answer: C) Fusion
Question: The balanced chemical equation for the reaction between hydrogen gas and oxygen gas to form water is:
A) 2H2 + O2 → 2H2O
B) H2 + O2 → H2O
C) H2O → H2 + O2
D) H2O → H2 + O
Answer: A) 2H2 + O2 → 2H2O
Question: In the reaction 2H2 + O2 → 2H2O, hydrogen and oxygen are:
A) Reactants
B) Products
C) Catalysts
D) Solvents
Answer: A) Reactants
Question: Stoichiometry is the study of:
A) Chemical kinetics
B) Chemical equilibrium
C) Chemical reactions and their products
D) Chemical composition and reactions
Answer: D) Chemical composition and reactions
Question: The limiting reactant in a chemical reaction is the reactant that:
A) Is present in the smallest amount
B) Is completely consumed in the reaction
C) Determines the amount of product formed
D) Both A and B
Answer: D) Both A and B
Question: What is the molarity of a solution containing 0.5 moles of solute in 250 mL of solution?
A) 0.02 M
B) 2.0 M
C) 5.0 M
D) 20.0 M
Answer: C) 5.0 M
Question: Boyle’s law describes the relationship between:
A) Pressure and temperature
B) Volume and temperature
C) Pressure and volume
D) Volume and moles
Answer: C) Pressure and volume
Question: The unit of pressure in the International System of Units (SI) is:
A) Atmosphere (atm)
B) Torr (mmHg)
C) Pascal (Pa)
D) Kilopascal (kPa)
Answer: C) Pascal (Pa)
Question: The ideal gas law equation is given by:
A) PV = nRT
B) PV = RT
C) P = nRT/V
D) PV = nT/V
Answer: A) PV = nRT
Question: Which of the following statements is TRUE about an ideal gas?
A) It occupies no volume
B) It exerts no pressure
C) It obeys all the gas laws at all temperatures and pressures
D) It has no mass
Answer: C) It obeys all the gas laws at all temperatures and pressures
Question: What is the volume of 1 mole of an ideal gas at STP (standard temperature and pressure)?
A) 22.4 L
B) 24.0 L
C) 25.0 L
D) 27.0 L
Answer: A) 22.4 L
Question: The total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each individual gas. This statement is known as:
A) Boyle’s law
B) Charles’s law
C) Dalton’s law
D) Gay-Lussac’s law
Answer: C) Dalton’s law
Question: Which of the following is NOT a colligative property of a solution?
A) Boiling point elevation
B) Freezing point depression
C) Vapor pressure lowering
D) Heat of fusion
Answer: D) Heat of fusion
Question: Raoult’s law describes the relationship between the vapor pressure of a solution and the:
A) Temperature of the solution
B) Concentration of the solute
C) Volume of the solution
D) Density of the solvent
Answer: B) Concentration of the solute
Question: The process of removing impurities from a solution by adding a solvent and then separating the pure solvent from the solution is called:
A) Distillation
B) Filtration
C) Evaporation
D) Recrystallization
Answer: A) Distillation
Question: The number of atoms in one mole of a substance is equal to:
A) Avogadro’s number
B) Boltzmann’s constant
C) Planck’s constant
D) Faraday’s constant
Answer: A) Avogadro’s number
Question: What is the mass percent of carbon in carbon dioxide (CO2)?
A) 27%
B) 33%
C) 50%
D) 75%
Answer: C) 50%
Question: The percentage composition of a compound is the:
A) Ratio of the masses of the elements in the compound
B) Ratio of the masses of the compound to the masses of the elements
C) Mass of the compound divided by its molar mass
D) Mass of each element in the compound divided by the total mass of the compound
Answer: D) Mass of each element in the compound divided by the total mass of the compound
Question: The empirical formula of a compound is CH2O. What is its molecular formula if its molar mass is 180 g/mol?
A) CH2O
B) C2H4O2
C) C3H6O3
D) C4H8O4
Answer: C) C3H6O3
Question: The reaction between sodium (Na) and chlorine (Cl2) to form sodium chloride (NaCl) is an example of:
A) Synthesis reaction
B) Decomposition reaction
C) Single replacement reaction
D) Double replacement reaction
Answer: A) Synthesis reaction
Question: The balanced chemical equation for the reaction between calcium carbonate (CaCO3) and hydrochloric acid (HCl) to form calcium chloride (CaCl2), carbon dioxide (CO2), and water (H2O) is:
A) CaCO3 + HCl → CaCl2 + CO2 + H2O
B) CaCO3 + 2HCl → CaCl2 + CO2 + H2O
C) CaCO3 + HCl → CaCl2 + CO + H2O
D) CaCO3 + HCl → CaCl + CO2 + H2O
Answer: B) CaCO3 + 2HCl → CaCl2 + CO2 + H2O
Question: The balanced chemical equation for the combustion of methane (CH4) in oxygen (O2) to form carbon dioxide (CO2) and water (H2O) is:
A) CH4 + O2 → CO2 + H2O
B) CH4 + 2O2 → CO2 + 2H2O
C) CH4 + O2 → CO + H2O
D) CH4 + 2O2 → CO + 2H2O
Answer: B) CH4 + 2O2 → CO2 + 2H2O
Question: What is the empirical formula of a compound if its molecular formula is C6H12O6?
A) CH2O
B) C2H4O2
C) C3H6O3
D) C6H12O6
Answer: A) CH2O
Question: Which of the following is a colligative property?
A) Boiling point
B) Melting point
C) Vapor pressure
D) All of the above
Answer: D) All of the above
Question: What is the volume occupied by 2 moles of an ideal gas at STP?
A) 11.2 L
B) 22.4 L
C) 44.8 L
D) 89.6 L
Answer: C) 44.8 L
Question: What is the formula mass of calcium phosphate, Ca3(PO4)2?
A) 100 g/mol
B) 310 g/mol
C) 310 amu
D) 100 amu
Answer: B) 310 g/mol
Question: A solution contains 0.5 moles of solute in 250 mL of solution. What is its molarity?
A) 0.1 M
B) 1.0 M
C) 2.0 M
D) 5.0 M
Answer: D) 5.0 M
Question: Which of the following gases is NOT considered an ideal gas under ordinary conditions?
A) Nitrogen (N2)
B) Oxygen (O2)
C) Carbon dioxide (CO2)
D) Hydrogen (H2)
Answer: C) Carbon dioxide (CO2)
