Q. The rate of a reaction doubles when the temperature is increased by 10°C. This is an example of which rule?
A.Arrhenius equation
B.Van 't Hoff rule
C.Le Chatelier's principle
D.Gibbs free energy
Solution
This is an example of Van 't Hoff rule, which states that the rate of reaction doubles for every 10°C increase in temperature.
Correct Answer: B — Van 't Hoff rule
Q. The rate of a reaction is defined as the change in concentration of a reactant or product per unit time. What is the unit of rate?
A.mol/L
B.mol/L·s
C.L/mol·s
D.1/s
Solution
The rate of reaction is expressed in terms of concentration change per unit time, hence the unit is mol/L·s.
Correct Answer: B — mol/L·s
Q. The rate of a reaction is directly proportional to the product of the concentrations of the reactants raised to their respective powers. This is known as what?
A.Rate law
B.Equilibrium constant
C.Reaction quotient
D.Catalytic law
Solution
This relationship is known as the rate law of the reaction.
Correct Answer: A — Rate law
Q. What does a large negative value of ΔG indicate about a reaction?
A.The reaction is highly spontaneous.
B.The reaction is non-spontaneous.
C.The reaction is at equilibrium.
D.The reaction requires a catalyst.
Solution
A large negative value of ΔG indicates that the reaction is highly spontaneous and favors the formation of products.
Correct Answer: A — The reaction is highly spontaneous.
Q. What does a negative ΔG indicate about a chemical reaction?
A.The reaction is at equilibrium.
B.The reaction is non-spontaneous.
C.The reaction is spontaneous.
D.The reaction requires energy input.
Solution
A negative ΔG indicates that the reaction is spontaneous under the given conditions.
Correct Answer: C — The reaction is spontaneous.
Q. What does a ΔG value of zero indicate about a reaction?
A.The reaction is spontaneous.
B.The reaction is at equilibrium.
C.The reaction is non-spontaneous.
D.The reaction is exothermic.
Solution
A ΔG value of zero indicates that the reaction is at equilibrium, meaning the forward and reverse reactions occur at the same rate.
Correct Answer: B — The reaction is at equilibrium.
Q. What does Raoult's Law state about the vapor pressure of a solution?
A.It is directly proportional to the mole fraction of the solvent.
B.It is inversely proportional to the mole fraction of the solute.
C.It is equal to the vapor pressure of the solute.
D.It is independent of temperature.
Solution
Raoult's Law states that the vapor pressure of a solvent in a solution is directly proportional to the mole fraction of the solvent.
Correct Answer: A — It is directly proportional to the mole fraction of the solvent.
Q. What does the Gibbs free energy change indicate?
A.Spontaneity of a reaction
B.Rate of a reaction
C.Equilibrium constant
D.Activation energy
Solution
The Gibbs free energy change indicates the spontaneity of a reaction; a negative value suggests spontaneity.
Correct Answer: A — Spontaneity of a reaction
Q. What does the term 'enthalpy of reaction' refer to?
A.The heat absorbed or released at constant pressure
B.The change in internal energy
C.The work done by the system
D.The temperature change during a reaction
Solution
The enthalpy of reaction refers to the heat absorbed or released at constant pressure.
Correct Answer: A — The heat absorbed or released at constant pressure
Q. What does the term 'entropy' refer to in thermodynamics?
A.Energy stored in a system
B.Disorder or randomness in a system
C.Heat content of a system
D.Pressure of a system
Solution
Entropy is a measure of the disorder or randomness in a system.
Correct Answer: B — Disorder or randomness in a system
Q. What does the term 'Gibbs free energy' indicate?
A.The total energy of a system
B.The energy available to do work
C.The heat content of a system
D.The entropy of a system
Solution
Gibbs free energy indicates the maximum reversible work that can be performed by a thermodynamic system at constant temperature and pressure.
Correct Answer: B — The energy available to do work
Q. What effect does increasing temperature have on the Gibbs Free Energy of an endothermic reaction?
A.ΔG increases.
B.ΔG decreases.
C.ΔG remains constant.
D.ΔG becomes zero.
Solution
For an endothermic reaction, increasing temperature generally decreases ΔG, making the reaction more favorable.
Correct Answer: B — ΔG decreases.
Q. What effect does increasing the concentration of a reactant have on the rate of a first-order reaction?
A.Increases the rate
B.Decreases the rate
C.No effect
D.Rate becomes zero
Solution
Increasing the concentration of a reactant in a first-order reaction increases the rate of the reaction.
Correct Answer: A — Increases the rate
Q. What happens to the boiling point of a liquid when the atmospheric pressure decreases?
A.It increases.
B.It decreases.
C.It remains the same.
D.It becomes unpredictable.
Solution
The boiling point of a liquid decreases with a decrease in atmospheric pressure.
Correct Answer: B — It decreases.
Q. What happens to the equilibrium constant if the reaction is reversed?
A.K remains the same
B.K is doubled
C.K is inverted
D.K is halved
Solution
When a reaction is reversed, the equilibrium constant for the reverse reaction is the reciprocal of the equilibrium constant for the forward reaction.
Correct Answer: C — K is inverted
Q. What happens to the equilibrium constant when a reaction is reversed?
A.It remains the same
B.It doubles
C.It is inverted
D.It is halved
Solution
When a reaction is reversed, the equilibrium constant is inverted (1/K).
Correct Answer: C — It is inverted
Q. What happens to the freezing point of a solvent when a non-volatile solute is added?
A.It increases
B.It decreases
C.It remains the same
D.It fluctuates
Solution
The freezing point of a solvent decreases when a non-volatile solute is added, a phenomenon known as freezing point depression.
Correct Answer: B — It decreases
Q. What happens to the kinetic energy of particles as a substance changes from solid to liquid?
A.It decreases
B.It remains the same
C.It increases
D.It fluctuates
Solution
The kinetic energy of particles increases as they gain energy to overcome intermolecular forces during melting.
Correct Answer: C — It increases
Q. What happens to the pressure of a gas if the volume is doubled at constant temperature?
A.It doubles
B.It halves
C.It remains the same
D.It quadruples
Solution
According to Boyle's Law, if the volume is doubled at constant temperature, the pressure halves.
Correct Answer: B — It halves
Q. What happens to the vapor pressure of a solution as the concentration of a non-volatile solute increases?
A.It increases.
B.It decreases.
C.It remains constant.
D.It fluctuates.
Solution
As the concentration of a non-volatile solute increases, the vapor pressure of the solution decreases according to Raoult's Law.
Correct Answer: B — It decreases.
Q. What happens to the vapor pressure of a solvent when a non-volatile solute is added?
A.It increases
B.It decreases
C.It remains the same
D.It fluctuates
Solution
The vapor pressure of a solvent decreases when a non-volatile solute is added due to the solute particles occupying space at the surface.
Correct Answer: B — It decreases
Q. What happens to the vapor pressure of a solvent when a volatile solute is added?
A.It increases.
B.It decreases.
C.It remains the same.
D.It becomes zero.
Solution
The addition of a volatile solute decreases the vapor pressure of the solvent due to the presence of solute molecules.
Correct Answer: B — It decreases.
Q. What happens to the volume of a gas if the temperature is increased at constant pressure?
A.It decreases
B.It increases
C.It remains the same
D.It becomes zero
Solution
According to Charles's law, the volume of a gas increases with an increase in temperature at constant pressure.
Correct Answer: B — It increases
Q. What is denaturation of proteins?
A.The process of protein synthesis
B.The loss of protein function due to structural changes
C.The formation of peptide bonds
D.The folding of proteins into their functional shape
Solution
Denaturation refers to the process where proteins lose their native structure and function due to external factors like heat or pH changes.
Correct Answer: B — The loss of protein function due to structural changes
Q. What is the basic building block of proteins?
A.Nucleotides
B.Fatty acids
C.Amino acids
D.Monosaccharides
Solution
Proteins are made up of amino acids, which are their basic building blocks.
Correct Answer: C — Amino acids
Q. What is the basic structural unit of proteins?
A.Nucleotide
B.Monosaccharide
C.Amino acid
D.Fatty acid
Solution
Proteins are made up of long chains of amino acids.
Correct Answer: C — Amino acid
Q. What is the basic unit of nucleic acids?
A.Amino acid
B.Nucleotide
C.Monosaccharide
D.Fatty acid
Solution
The basic unit of nucleic acids, such as DNA and RNA, is the nucleotide.
Correct Answer: B — Nucleotide
Q. What is the boiling point of a liquid?
A.The temperature at which vapor pressure equals atmospheric pressure
B.The temperature at which a liquid freezes
C.The temperature at which a liquid evaporates
D.The temperature at which a liquid condenses
Solution
The boiling point is defined as the temperature at which the vapor pressure of a liquid equals the atmospheric pressure.
Correct Answer: A — The temperature at which vapor pressure equals atmospheric pressure
Q. What is the boiling point trend among alcohols, ethers, and alkanes?
A.Alcohols > Ethers > Alkanes
B.Ethers > Alcohols > Alkanes
C.Alkanes > Ethers > Alcohols
D.All have the same boiling point
Solution
Alcohols have higher boiling points than ethers and alkanes due to hydrogen bonding.
Correct Answer: A — Alcohols > Ethers > Alkanes
Q. What is the bond angle around the carbon atoms in an alkyne?
A.120 degrees
B.180 degrees
C.109.5 degrees
D.90 degrees
Solution
The bond angle around the carbon atoms in an alkyne is approximately 180 degrees due to linear geometry.
