All Free Chemistry MCQs with Answers

• A. Have close packing
• B. Have low empty spaces
• C. Become less tightly held
• D. Have strong electrostatic forces

Explanation: Lattice energy is the energy released when ions come together to form a crystal lattice.

• A. Accept me and Della for what we are.
• B. Accept Della and me for what we are.
• C. Accept me and Della for what I am.
• D. Accept Della and me for what she is.

Explanation: The correct answer is 'Accept Della and me for what we are.' This option correctly uses 'Della and me' as the objects of the verb…

• A. Li2CO3
• B. KI
• C. NaCl
• D. Both option A and B

Explanation: Li₂CO₃ (Lithium carbonate)Endothermic dissolution → solubility increases with temperature.KI (Potassium iodide)Dissolution is endothermic…

• A. A solution freezes at a lower temperature than the pure solvent
• B. A solution boils at a higher temperature than the pure solvent.
• C. 0.1 M NaCl solution and 0.1 m sugar solution have the same boiling point
• D. Osmosis cannot take place without a semi-permeable membrane.

Explanation: Molarity is the moles of solute in 1 litre of solution Molality is the moles of solute per 1 kg of solvent.

• A. decreases
• B. increases
• C. neither decreases nor increases
• D. none

Explanation: The presence of common ions in a solution can affect the solubility of a slightly soluble ionic compound.

• A. W. Roentgen
• B. De Broglie
• C. Young
• D. Michelson

Explanation: The correct answer is A. Wilhelm Conrad Roentgen discovered X-rays on November 8, 1895, while experimenting with cathode-ray tubes.

• A. q = H at constant T; q = E at constant V
• B. q = H at constant V; q = E at constant P
• C. q = H at constant P; q = E at constant V
• D. q = H = E at constant P or at constant V

Explanation: q = H = E at constant P or at constant V: This statement is true. At constant pressure (P) or constant volume (V), the heat transfer (q)…

• A. Change in state of the system may occur
• B. Temperature of the system may rise
• C. Chemical reaction may take place
• D. All

Explanation: Explanation: An increase in internal energy can lead to various changes, including changes in state, a rise in temperature, and potential…

• A. K
• B. KCal
• C. Cal
• D. GJ

Explanation: Explanation: The unit of heat in the SI system is the calorie (Cal).

• A. qp>qv
• B. delta E<Delta H
• C. delta E>Delta H
• D. Both a & b

Explanation: Explanation: Both statements are correct. ΔE represents the change in internal energy and can be less than ΔH in some instances…

• A. can be measured by calorimeter
• B. calculated by Hess's law
• C. none
• D. both a and b

Explanation: Explanation: Enthalpy change can be measured by a calorimeter and calculated using Hess's law.

• A. Heat
• B. Pressure
• C. Volume
• D. Enthalpy

Explanation: A state function is a property whose value depends only on the current state of a system, not on the path taken to reach that state.

• A. The first law of thermodynamics is not sufficient to predict the direction of a process
• B. In the case of an exothermic reaction, the overall enthalpy of the products is greater than that of the reactants
• C. For the reaction H₂(g) + Br₂(l) → 2HBr(g), the enthalpy change can be calculated from bond enthalpy data alone
• D. At 298K and 1 atm pressure, diamond's standard enthalpy of formation is zero

Explanation: The first law deals with the conservation of energy but provides no information about the direction in which a process will spontaneously…

• A. ΔH is positive for an exothermic reaction
• B. ΔH is negative for an endothermic reaction
• C. The heat of neutralization of a strong acid with a strong base is always the same
• D. The enthalpy of fusion is negative

Explanation: The neutralization of any strong acid with any strong base always involves the same net ionic reaction: H⁺(aq) + OH⁻(aq) → H₂O(l).

• A. C(s) + O₂(g) → CO₂(g)
• B. 2H₂(g) + O₂(g) → 2H₂O(l)
• C. N₂(g) + O₂(g) → 2NO(g)
• D. CaO(s) + H₂O(l) → Ca(OH)₂(aq)

Explanation: The formation of nitric oxide (NO) from nitrogen and oxygen is a highly endothermic reaction, meaning it requires a significant input of…

• A. ΔH is positive for endothermic reactions.
• B. ΔH is negative for exothermic reactions.
• C. In the equation ΔE = q - PΔV, where q = ΔV.
• D. All the above are correct.

Explanation: Option C is the correct answer because it contains an incorrect statement.

• A. Exothermic
• B. Spontaneous
• C. Non-Spontaneous
• D. None of these

Explanation: It is a spontaneous process as entropy increases with the change in state.

• A. Al2O3
• B. B2O3
• C. CCL4
• D. All of these options are correct

Explanation: Frankly speaking, We don't know the absolute enthalpy of a substance because we don't know where absolute Zero is.

• A. Rotational & vibrational
• B. Translation & rotational
• C. Rotational, vibrational and translatio
• D. All of these

Explanation: Kinetic energy is the sum of translational, rotational, and vibrational kinetic energies, representing the various forms of motion…

• A. Internal Energy
• B. Enthalpy
• C. Work
• D. None of these options are correct

Explanation: Option C is correct since work can not be a state function as it is proportional to the distance an object is moved.