Q. In a solution of a non-volatile solute, how does the vapor pressure compare to that of the pure solvent?
A.
Higher than the pure solvent
B.
Lower than the pure solvent
C.
Equal to the pure solvent
D.
Depends on the temperature
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Solution
The presence of a non-volatile solute lowers the vapor pressure of the solvent compared to that of the pure solvent.
Correct Answer: B — Lower than the pure solvent
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Q. In a solution of two volatile components A and B, if the mole fraction of A is 0.6, what is the vapor pressure of the solution if the vapor pressure of pure A is 100 mmHg and that of pure B is 50 mmHg?
A.
80 mmHg
B.
90 mmHg
C.
70 mmHg
D.
60 mmHg
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Solution
Using Raoult's Law, the vapor pressure of the solution is P_total = (0.6 * 100) + (0.4 * 50) = 60 + 20 = 80 mmHg.
Correct Answer: B — 90 mmHg
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Q. In a solution of volatile components A and B, if the vapor pressure of A is 80 mmHg and that of B is 20 mmHg, what is the total vapor pressure?
A.
100 mmHg
B.
80 mmHg
C.
60 mmHg
D.
20 mmHg
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Solution
The total vapor pressure of a solution is the sum of the partial vapor pressures of its components: 80 mmHg + 20 mmHg = 100 mmHg.
Correct Answer: A — 100 mmHg
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Q. In a spontaneous process, the change in Gibbs free energy (ΔG) is:
A.
Positive
B.
Negative
C.
Zero
D.
Undefined
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Solution
For a spontaneous process, the change in Gibbs free energy (ΔG) is negative.
Correct Answer: B — Negative
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Q. In a static equilibrium problem, if the sum of clockwise moments equals the sum of counterclockwise moments, what can be concluded?
A.
The object is in equilibrium
B.
The object is accelerating
C.
The object is in motion
D.
The object is unstable
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Solution
If the sum of clockwise moments equals the sum of counterclockwise moments, the object is in equilibrium.
Correct Answer: A — The object is in equilibrium
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Q. In a system at equilibrium, if the concentration of reactants is increased, what will happen to the equilibrium position?
A.
Shift to the right
B.
Shift to the left
C.
No change
D.
Depends on temperature
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Solution
According to Le Chatelier's principle, increasing the concentration of reactants will shift the equilibrium position to the right to favor the formation of products.
Correct Answer: A — Shift to the right
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Q. In a system of two blocks connected by a spring, if the spring is compressed, what is the condition for equilibrium?
A.
Net force acting on the system is zero
B.
Net momentum of the system is constant
C.
Kinetic energy is maximized
D.
Potential energy is minimized
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Solution
For equilibrium, the net force acting on the system must be zero.
Correct Answer: A — Net force acting on the system is zero
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Q. In a system where two forces act at an angle of 90 degrees, how do you find the resultant force?
A.
By adding the forces algebraically
B.
Using the Pythagorean theorem
C.
By taking the average of the two forces
D.
By subtracting the smaller force from the larger force
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Solution
The resultant force can be found using the Pythagorean theorem since the forces are perpendicular.
Correct Answer: B — Using the Pythagorean theorem
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Q. In a zero-order reaction, how does the rate change with respect to concentration?
A.
Increases linearly
B.
Decreases linearly
C.
Remains constant
D.
Increases exponentially
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Solution
In a zero-order reaction, the rate is constant and does not depend on the concentration of reactants.
Correct Answer: C — Remains constant
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Q. In a zero-order reaction, if the rate constant k is 5 mol/L/s, how long will it take for the concentration to decrease from 2 mol/L to 0 mol/L?
A.
0.4 s
B.
0.5 s
C.
0.6 s
D.
0.8 s
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Solution
For a zero-order reaction, time = (initial concentration - final concentration) / k = (2 - 0) / 5 = 0.4 s.
Correct Answer: C — 0.6 s
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Q. In a zero-order reaction, the rate of reaction is independent of which of the following?
A.
Concentration of reactants
B.
Temperature
C.
Catalyst
D.
All of the above
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Solution
In a zero-order reaction, the rate of reaction is independent of the concentration of reactants.
Correct Answer: A — Concentration of reactants
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Q. In an endothermic reaction, the enthalpy of the products is ____ than that of the reactants.
A.
higher
B.
lower
C.
equal
D.
unpredictable
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Solution
In an endothermic reaction, the enthalpy of the products is higher than that of the reactants.
Correct Answer: A — higher
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Q. In an ideal solution, the enthalpy of mixing is:
A.
Positive
B.
Negative
C.
Zero
D.
Varies with concentration
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Solution
In an ideal solution, the enthalpy of mixing is zero, indicating no heat is absorbed or released during mixing.
Correct Answer: C — Zero
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Q. In an irreversible process, the change in entropy of the universe is:
A.
Zero
B.
Positive
C.
Negative
D.
Undefined
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Solution
In an irreversible process, the change in entropy of the universe is positive, indicating that the total entropy increases.
Correct Answer: B — Positive
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Q. In an isothermal process, the temperature of the system remains constant. What is the work done by the gas during expansion?
A.
Zero
B.
nRT ln(Vf/Vi)
C.
nRT (Vf - Vi)
D.
nR (Tf - Ti)
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Solution
In an isothermal process, the work done by the gas is given by W = nRT ln(Vf/Vi).
Correct Answer: B — nRT ln(Vf/Vi)
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Q. In electrochemistry, what does the term 'reduction' refer to?
A.
Loss of electrons
B.
Gain of electrons
C.
Loss of protons
D.
Gain of protons
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Solution
Reduction refers to the gain of electrons in a chemical reaction.
Correct Answer: B — Gain of electrons
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Q. In molecular orbital theory, which of the following orbitals is filled first?
A.
σ2s
B.
σ*2s
C.
π2p
D.
σ2p
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Solution
According to the Aufbau principle, the σ2s orbital is filled first before any other orbitals.
Correct Answer: A — σ2s
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Q. In molecular orbital theory, which of the following orbitals is the highest energy in O2?
A.
σ2p
B.
π2p
C.
σ2s
D.
π2s
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Solution
In O2, the π2p orbitals are the highest energy orbitals.
Correct Answer: B — π2p
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Q. In molecular orbital theory, which of the following statements is correct regarding the energy levels of orbitals?
A.
σ orbitals are always lower than π orbitals.
B.
π orbitals are always lower than σ orbitals.
C.
σ* orbitals are always higher than π* orbitals.
D.
Energy levels can vary based on the atoms involved.
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Solution
The energy levels of molecular orbitals can vary depending on the specific atoms and their electronegativities.
Correct Answer: D — Energy levels can vary based on the atoms involved.
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Q. In the complex [Ni(CO)4], what is the hybridization of the nickel atom?
A.
sp
B.
sp2
C.
sp3
D.
d2sp3
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Solution
Nickel in [Ni(CO)4] undergoes sp3 hybridization as it forms four sigma bonds with CO ligands.
Correct Answer: C — sp3
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Q. In the context of adsorption, what does the term 'saturation' refer to?
A.
Complete coverage of the adsorbent surface
B.
Maximum temperature for adsorption
C.
Equilibrium state of adsorption and desorption
D.
None of the above
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Solution
Saturation refers to the complete coverage of the adsorbent surface by the adsorbate.
Correct Answer: A — Complete coverage of the adsorbent surface
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Q. In the equilibrium constant expression Kc, what is the unit for Kc if the reaction is A(g) + B(g) ⇌ C(g)?
A.
mol/L
B.
L/mol
C.
dimensionless
D.
mol^2/L^2
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Solution
The equilibrium constant Kc is dimensionless because it is a ratio of concentrations raised to their stoichiometric coefficients.
Correct Answer: C — dimensionless
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Q. In the equilibrium reaction 2SO2(g) + O2(g) ⇌ 2SO3(g), if SO2 is added, what will be the effect on the equilibrium?
A.
Shift to the right
B.
Shift to the left
C.
No change
D.
Increase in pressure
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Solution
Adding SO2 will shift the equilibrium to the right to produce more SO3, according to Le Chatelier's principle.
Correct Answer: A — Shift to the right
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Q. In the equilibrium reaction 2SO2(g) + O2(g) ⇌ 2SO3(g), what happens if SO3 is removed?
A.
Shift to the right
B.
Shift to the left
C.
No change
D.
Increase in pressure
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Solution
Removing SO3 will shift the equilibrium to the right to produce more SO3.
Correct Answer: A — Shift to the right
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Q. In the Freundlich adsorption isotherm, which parameter indicates the extent of adsorption?
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Solution
In the Freundlich isotherm, K is the adsorption coefficient that indicates the extent of adsorption.
Correct Answer: A — K
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Q. In the ideal gas equation PV=nRT, what does 'n' represent?
A.
Pressure
B.
Volume
C.
Number of moles
D.
Temperature
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Solution
'n' represents the number of moles of the gas in the ideal gas equation.
Correct Answer: C — Number of moles
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Q. In the Langmuir adsorption isotherm, what assumption is made about the adsorption sites?
A.
They are identical and have the same energy
B.
They are different and have varying energy
C.
They can accommodate multiple layers
D.
They are not limited in number
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Solution
The Langmuir isotherm assumes that all adsorption sites are identical and have the same energy.
Correct Answer: A — They are identical and have the same energy
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Q. In the Langmuir adsorption isotherm, what does the term 'b' represent?
A.
Adsorption energy
B.
Surface area
C.
Equilibrium constant
D.
Adsorption capacity
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Solution
'b' in the Langmuir isotherm represents the equilibrium constant related to the adsorption process.
Correct Answer: C — Equilibrium constant
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Q. In the molecular orbital diagram of diatomic nitrogen (N2), which orbitals are filled first?
A.
σ2s, σ*2s
B.
σ2p, π2p
C.
π2p, σ2p
D.
σ*2p, π*2p
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Solution
In N2, the 2s orbitals (σ2s and σ*2s) are filled before the 2p orbitals.
Correct Answer: A — σ2s, σ*2s
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Q. In the molecular orbital theory, which of the following is true for the π molecular orbitals?
A.
They are formed by end-to-end overlap.
B.
They are lower in energy than σ orbitals.
C.
They can accommodate a maximum of 2 electrons.
D.
They are always bonding.
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Solution
π molecular orbitals can accommodate a maximum of 2 electrons, similar to all molecular orbitals.
Correct Answer: C — They can accommodate a maximum of 2 electrons.
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