Chemistry (School & UG)
Q. What is the effect of increasing the concentration of an acid on its pH?
A.
pH increases
B.
pH decreases
C.
pH remains constant
D.
pH fluctuates
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Solution
Increasing the concentration of an acid decreases its pH, as pH is inversely related to the concentration of H+ ions.
Correct Answer: B — pH decreases
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Q. What is the effect of increasing the concentration of reactants on the rate of reaction for a zero-order reaction?
A.
Rate increases
B.
Rate decreases
C.
Rate remains constant
D.
Rate becomes negative
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Solution
For a zero-order reaction, the rate is independent of the concentration of reactants, so it remains constant.
Correct Answer: C — Rate remains constant
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Q. What is the effect of increasing the electronegativity difference between two bonded atoms?
A.
Increases bond length
B.
Decreases bond strength
C.
Increases ionic character
D.
Decreases dipole moment
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Solution
An increasing electronegativity difference leads to greater ionic character in the bond, making it more polar.
Correct Answer: C — Increases ionic character
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Q. What is the effect of increasing the electronegativity of an atom bonded to hydrogen?
A.
Decreases bond strength
B.
Increases bond strength
C.
Decreases acidity
D.
Increases acidity
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Solution
Increasing the electronegativity of an atom bonded to hydrogen increases the acidity of the compound.
Correct Answer: D — Increases acidity
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Q. What is the effect of increasing the electronegativity of atoms in a molecule on its dipole moment?
A.
Increases dipole moment
B.
Decreases dipole moment
C.
No effect
D.
Reverses dipole moment
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Solution
Increasing electronegativity of atoms in a molecule increases the dipole moment as the difference in charge distribution becomes greater.
Correct Answer: A — Increases dipole moment
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Q. What is the effect of increasing the number of alkyl groups on the basicity of amines?
A.
Increases basicity
B.
Decreases basicity
C.
No effect
D.
Depends on the solvent
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Solution
Increasing the number of alkyl groups generally increases the basicity of amines due to the electron-donating effect.
Correct Answer: A — Increases basicity
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Q. What is the effect of increasing the number of gas molecules in a container at constant volume?
A.
Pressure decreases
B.
Pressure increases
C.
Temperature decreases
D.
Volume increases
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Solution
Increasing the number of gas molecules in a container at constant volume increases the frequency of collisions with the walls, thus increasing pressure.
Correct Answer: B — Pressure increases
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Q. What is the effect of increasing the number of moles of gas in a container at constant temperature and volume?
A.
Pressure decreases
B.
Pressure remains constant
C.
Pressure increases
D.
Temperature increases
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Solution
According to Avogadro's Law, increasing the number of moles of gas increases pressure if volume and temperature are constant.
Correct Answer: C — Pressure increases
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Q. What is the effect of increasing the number of moles of gas in a container at constant volume and temperature?
A.
Pressure decreases
B.
Pressure increases
C.
Volume increases
D.
Temperature increases
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Solution
According to Avogadro's Law, increasing the number of moles of gas at constant volume and temperature will increase the pressure.
Correct Answer: B — Pressure increases
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Q. What is the effect of increasing the oxidation state of a transition metal on its ionic radius?
A.
Increases
B.
Decreases
C.
Remains the same
D.
Varies unpredictably
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Solution
Increasing the oxidation state of a transition metal generally decreases its ionic radius due to increased nuclear charge.
Correct Answer: B — Decreases
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Q. What is the effect of increasing the oxidation state of a transition metal on its ability to act as a Lewis acid?
A.
Increases
B.
Decreases
C.
No effect
D.
Varies unpredictably
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Solution
Increasing the oxidation state of a transition metal generally increases its ability to act as a Lewis acid due to a higher positive charge attracting electron pairs more strongly.
Correct Answer: A — Increases
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Q. What is the effect of increasing the path length in a UV-Vis spectrophotometer?
A.
Decreases absorbance
B.
Increases absorbance
C.
No effect on absorbance
D.
Increases wavelength
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Solution
Increasing the path length increases the absorbance according to Beer-Lambert Law.
Correct Answer: B — Increases absorbance
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Q. What is the effect of increasing the pressure on the equilibrium of the reaction 2SO2(g) + O2(g) ⇌ 2SO3(g)?
A.
Shifts to the left
B.
Shifts to the right
C.
No effect
D.
Increases the rate of reaction
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Solution
Increasing the pressure will shift the equilibrium to the right, favoring the formation of SO3, as there are fewer moles of gas on the right side.
Correct Answer: B — Shifts to the right
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Q. What is the effect of increasing the surface area of a solid reactant on the reaction rate?
A.
No effect on the rate
B.
Decreases the rate
C.
Increases the rate
D.
Only affects gas-phase reactions
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Solution
Increasing the surface area of a solid reactant increases the rate of reaction by providing more area for collisions.
Correct Answer: C — Increases the rate
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Q. What is the effect of increasing the temperature on the cell potential of an electrochemical cell?
A.
Increases
B.
Decreases
C.
No effect
D.
Depends on the reaction
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Solution
The effect of temperature on cell potential depends on the reaction's enthalpy change (ΔH).
Correct Answer: D — Depends on the reaction
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Q. What is the effect of increasing the temperature on the rate of a chemical reaction?
A.
Decreases the rate
B.
Increases the rate
C.
No effect
D.
Depends on the reaction
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Solution
Increasing temperature generally increases the kinetic energy of molecules, leading to more frequent and effective collisions, thus increasing the reaction rate.
Correct Answer: B — Increases the rate
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Q. What is the effect of removing a product from a reaction at equilibrium?
A.
Shifts equilibrium to the right
B.
Shifts equilibrium to the left
C.
No effect on equilibrium
D.
Increases the rate of reaction
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Solution
Removing a product will shift the equilibrium to the right to produce more products, in accordance with Le Chatelier's Principle.
Correct Answer: A — Shifts equilibrium to the right
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Q. What is the effect of temperature on physisorption?
A.
Increases with temperature
B.
Decreases with temperature
C.
No effect
D.
Depends on the adsorbate
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Solution
Physisorption typically decreases with increasing temperature because the kinetic energy of the molecules increases, overcoming the weak van der Waals forces.
Correct Answer: B — Decreases with temperature
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Q. What is the effect of temperature on the rate constant of a reaction according to the Arrhenius equation?
A.
Rate constant decreases with temperature
B.
Rate constant increases with temperature
C.
Rate constant is unaffected by temperature
D.
Rate constant is only affected by activation energy
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Solution
According to the Arrhenius equation, an increase in temperature generally leads to an increase in the rate constant, k.
Correct Answer: B — Rate constant increases with temperature
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Q. What is the effect of temperature on the rate of a chemical reaction according to the Arrhenius equation?
A.
Rate decreases exponentially with temperature
B.
Rate increases linearly with temperature
C.
Rate increases exponentially with temperature
D.
Rate remains constant regardless of temperature
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Solution
According to the Arrhenius equation, the rate constant increases exponentially with an increase in temperature, leading to a higher reaction rate.
Correct Answer: C — Rate increases exponentially with temperature
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Q. What is the effect of temperature on the rate of a chemical reaction?
A.
It decreases the rate
B.
It has no effect
C.
It increases the rate
D.
It can either increase or decrease the rate
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Solution
According to the Arrhenius equation, an increase in temperature generally increases the kinetic energy of molecules, leading to a higher reaction rate.
Correct Answer: C — It increases the rate
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Q. What is the effect of temperature on titration results?
A.
It has no effect
B.
It can change the solubility of the analyte
C.
It affects the volume of the titrant
D.
It alters the pH of the solutions
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Solution
Temperature can affect the solubility of the analyte and the reaction kinetics, potentially leading to variations in titration results.
Correct Answer: B — It can change the solubility of the analyte
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Q. What is the effective nuclear charge (Z_eff) experienced by a 3p electron in phosphorus (atomic number 15)?
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Solution
Using Slater's rules, Z_eff = Z - S. For P, Z = 15 and S = 8, so Z_eff = 15 - 8 = 7.
Correct Answer: C — 7
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Q. What is the effective nuclear charge (Z_eff) for a 3s electron in sodium (Na)?
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Solution
Z_eff = Z - S; for Na, Z = 11, S (shielding from 1s and 2s) ≈ 3. Thus, Z_eff = 11 - 3 = 8.
Correct Answer: D — 8
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Q. What is the effective nuclear charge (Z_eff) for a 3s electron in sodium (Z=11)?
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Solution
Using Slater's rules, Z_eff = Z - S; for Na, S = 3 (from 1s and 2s electrons). Thus, Z_eff = 11 - 3 = 8.
Correct Answer: C — 8
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Q. What is the electron affinity of chlorine in kJ/mol?
A.
-349 kJ/mol
B.
-328 kJ/mol
C.
-300 kJ/mol
D.
-400 kJ/mol
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Solution
The electron affinity of chlorine is approximately -349 kJ/mol.
Correct Answer: A — -349 kJ/mol
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Q. What is the electron configuration of a chlorine atom?
A.
1s2 2s2 2p6 3s2 3p5
B.
1s2 2s2 2p6 3s2 3p6
C.
1s2 2s2 2p6 3s2 3p4
D.
1s2 2s2 2p6 3s2 3p3
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Solution
Chlorine has 17 electrons, and its electron configuration is 1s2 2s2 2p6 3s2 3p5.
Correct Answer: A — 1s2 2s2 2p6 3s2 3p5
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Q. What is the electron configuration of a neutral atom of sulfur (S)?
A.
[Ne] 3s2 3p4
B.
[He] 2s2 2p6 3s2 3p4
C.
[Ar] 4s2 3d10 4p4
D.
[Ne] 3s2 3p6
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Solution
Sulfur has 16 electrons, and its electron configuration is [Ne] 3s2 3p4.
Correct Answer: A — [Ne] 3s2 3p4
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Q. What is the electron configuration of a neutral oxygen atom?
A.
1s2 2s2 2p4
B.
1s2 2s2 2p6
C.
1s2 2s2 2p3
D.
1s2 2s2 2p5
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Solution
Oxygen has 8 electrons, and its electron configuration is 1s2 2s2 2p4.
Correct Answer: A — 1s2 2s2 2p4
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Q. What is the electron configuration of a neutral sulfur atom?
A.
1s2 2s2 2p6 3s2 3p4
B.
1s2 2s2 2p6 3s2 3p6
C.
1s2 2s2 2p6 3s2 3p3
D.
1s2 2s2 2p6 3s2 3p5
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Solution
Sulfur has 16 electrons, and its electron configuration is 1s2 2s2 2p6 3s2 3p4.
Correct Answer: A — 1s2 2s2 2p6 3s2 3p4
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