Q. Which of the following reactions is an example of a disproportionation reaction? (2023)
A.
2H2O2 → 2H2O + O2
B.
2Na + Cl2 → 2NaCl
C.
Zn + CuSO4 → ZnSO4 + Cu
D.
Fe + 2HCl → FeCl2 + H2
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Solution
In the reaction 2H2O2 → 2H2O + O2, the oxidation state of oxygen changes from -1 in H2O2 to 0 in O2, indicating that it is both oxidized and reduced.
Correct Answer: A — 2H2O2 → 2H2O + O2
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Q. Which of the following reactions is an example of a redox reaction? (2023)
A.
H2 + Cl2 → 2HCl
B.
NaOH + HCl → NaCl + H2O
C.
CaCO3 → CaO + CO2
D.
C + O2 → CO2
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Solution
The reaction C + O2 → CO2 is a redox reaction because carbon is oxidized and oxygen is reduced.
Correct Answer: D — C + O2 → CO2
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Q. Which of the following reactions is an example of hydrogenation? (2023)
A.
Addition of H2 to ethene
B.
Decomposition of water
C.
Formation of ammonia from nitrogen and hydrogen
D.
Combustion of hydrogen
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Solution
Hydrogenation refers to the addition of hydrogen (H2) to unsaturated hydrocarbons, such as the addition to ethene to form ethane.
Correct Answer: A — Addition of H2 to ethene
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Q. Which of the following reactions is characteristic of aldehydes? (2023)
A.
Oxidation to carboxylic acids
B.
Reduction to alcohols
C.
Condensation with alcohols
D.
All of the above
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Solution
Aldehydes can undergo oxidation to form carboxylic acids, reduction to form alcohols, and condensation with alcohols to form hemiacetals.
Correct Answer: D — All of the above
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Q. Which of the following represents the ideal gas constant? (2022)
A.
R = 0.0821 L·atm/(K·mol)
B.
R = 8.314 J/(K·mol)
C.
Both A and B
D.
None of the above
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Solution
The ideal gas constant can be represented as R = 0.0821 L·atm/(K·mol) or R = 8.314 J/(K·mol).
Correct Answer: C — Both A and B
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Q. Which of the following solids has a high degree of anisotropy? (2019)
A.
Ionic solids
B.
Covalent solids
C.
Metallic solids
D.
Molecular solids
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Solution
Covalent solids exhibit a high degree of anisotropy due to their directional bonding.
Correct Answer: B — Covalent solids
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Q. Which of the following solids has a high thermal conductivity? (2019)
A.
Ionic solids
B.
Covalent solids
C.
Metallic solids
D.
Molecular solids
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Solution
Metallic solids have high thermal conductivity due to the presence of free-moving electrons.
Correct Answer: C — Metallic solids
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Q. Which of the following solutions has the highest boiling point elevation? (2020)
A.
0.1 M NaCl
B.
0.1 M KCl
C.
0.1 M CaCl2
D.
0.1 M MgCl2
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Solution
Boiling point elevation is proportional to the number of particles in solution. CaCl2 dissociates into 3 ions (1 Ca²⁺ and 2 Cl⁻), giving the highest elevation.
Correct Answer: C — 0.1 M CaCl2
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Q. Which of the following species can act as an oxidizing agent? (2023)
A.
Na+
B.
Cl-
C.
H2O
D.
MnO4-
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Solution
MnO4- is a strong oxidizing agent because it can gain electrons and be reduced to Mn2+.
Correct Answer: D — MnO4-
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Q. Which of the following species is oxidized in the reaction 2Na + Cl2 → 2NaCl? (2023)
A.
Na
B.
Cl2
C.
NaCl
D.
None
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Solution
In this reaction, sodium (Na) is oxidized as it loses electrons to form Na+.
Correct Answer: A — Na
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Q. Which of the following species is the strongest oxidizing agent? (2023)
A.
F2
B.
Cl2
C.
Br2
D.
I2
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Solution
F2 is the strongest oxidizing agent among the halogens due to its high electronegativity and ability to gain electrons.
Correct Answer: A — F2
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Q. Which of the following statements about alcohols is correct? (2022)
A.
They are all soluble in water.
B.
They have higher boiling points than alkanes.
C.
They cannot form hydrogen bonds.
D.
They are all volatile.
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Solution
Alcohols have higher boiling points than alkanes due to the presence of hydrogen bonding.
Correct Answer: B — They have higher boiling points than alkanes.
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Q. Which of the following statements about alcohols is incorrect? (2022)
A.
They can form hydrogen bonds.
B.
They are generally soluble in water.
C.
They have higher boiling points than alkanes.
D.
All alcohols are volatile.
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Solution
Not all alcohols are volatile; for example, long-chain alcohols have lower volatility.
Correct Answer: D — All alcohols are volatile.
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Q. Which of the following statements about chemisorption is true? (2022)
A.
It is a reversible process
B.
It involves the formation of strong chemical bonds
C.
It occurs at low temperatures
D.
It is independent of the nature of the adsorbate
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Solution
Chemisorption involves the formation of strong chemical bonds between the adsorbate and the surface, making it generally irreversible.
Correct Answer: B — It involves the formation of strong chemical bonds
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Q. Which of the following statements about hydrogen is incorrect? (2019)
A.
Hydrogen is the lightest element.
B.
Hydrogen can form covalent bonds.
C.
Hydrogen exists as a diatomic molecule in nature.
D.
Hydrogen is a metal at room temperature.
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Solution
Hydrogen is a non-metal at room temperature and does not exhibit metallic properties.
Correct Answer: D — Hydrogen is a metal at room temperature.
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Q. Which of the following statements about plasma is true? (2023)
A.
It has a definite shape and volume
B.
It is a good conductor of electricity
C.
It has low energy
D.
It is the most common state of matter in the universe
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Solution
Plasma is the most common state of matter in the universe, found in stars and interstellar space.
Correct Answer: D — It is the most common state of matter in the universe
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Q. Which of the following statements about solutions is true? (2023)
A.
Solutes increase the boiling point of solvents
B.
Solutes decrease the freezing point of solvents
C.
Both A and B
D.
Neither A nor B
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Solution
Both statements are true; solutes affect the colligative properties of solvents.
Correct Answer: C — Both A and B
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Q. Which of the following statements is true about a galvanic cell? (2020)
A.
It converts chemical energy to electrical energy
B.
It requires an external power source
C.
It is always non-spontaneous
D.
It operates at constant temperature only
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Solution
A galvanic cell converts chemical energy into electrical energy spontaneously.
Correct Answer: A — It converts chemical energy to electrical energy
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Q. Which of the following statements is true about alkali metals? (2023)
A.
They are good conductors of electricity
B.
They have high ionization energies
C.
They are found in nature in free state
D.
They form acidic oxides
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Solution
Alkali metals are good conductors of electricity due to the presence of free-moving electrons.
Correct Answer: A — They are good conductors of electricity
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Q. Which of the following statements is true about alkenes? (2019)
A.
They contain at least one double bond
B.
They are saturated hydrocarbons
C.
They have a general formula of C_nH_(2n+2)
D.
They cannot undergo addition reactions
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Solution
Alkenes are characterized by the presence of at least one double bond between carbon atoms.
Correct Answer: A — They contain at least one double bond
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Q. Which of the following statements is true about aromatic compounds? (2022)
A.
They are always saturated
B.
They contain a benzene ring
C.
They are non-polar
D.
They do not undergo electrophilic substitution
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Solution
Aromatic compounds are characterized by the presence of a benzene ring, which is a stable cyclic structure.
Correct Answer: B — They contain a benzene ring
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Q. Which of the following statements is true about exothermic reactions? (2019)
A.
They absorb heat.
B.
They release heat.
C.
They require energy input.
D.
They have a positive enthalpy change.
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Solution
Exothermic reactions release heat to the surroundings, resulting in a negative enthalpy change.
Correct Answer: B — They release heat.
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Q. Which of the following statements is true about phenols? (2023)
A.
They are stronger acids than alcohols
B.
They do not react with bases
C.
They are less soluble in water than alcohols
D.
They are non-toxic
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Solution
Phenols are stronger acids than alcohols due to the resonance stabilization of the phenoxide ion.
Correct Answer: A — They are stronger acids than alcohols
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Q. Which of the following statements is true about the equilibrium constant? (2019)
A.
Kc changes with temperature.
B.
Kc is dependent on the concentration of reactants.
C.
Kc is the same for all reactions at a given temperature.
D.
Kc is always greater than 1.
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Solution
The equilibrium constant Kc is temperature-dependent; it changes with temperature but is constant for a given reaction at a specific temperature.
Correct Answer: A — Kc changes with temperature.
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Q. Which of the following statements is true for a galvanic cell? (2020)
A.
It converts chemical energy to electrical energy
B.
It requires an external power source
C.
It is always non-spontaneous
D.
It operates at constant temperature only
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Solution
A galvanic cell converts chemical energy into electrical energy spontaneously.
Correct Answer: A — It converts chemical energy to electrical energy
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Q. Which of the following statements is true regarding aldehydes? (2023)
A.
They cannot form hydrogen bonds
B.
They are generally more reactive than ketones
C.
They have higher boiling points than ketones
D.
They are less soluble in water than ketones
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Solution
Aldehydes are generally more reactive than ketones due to the presence of the hydrogen atom attached to the carbonyl carbon.
Correct Answer: B — They are generally more reactive than ketones
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Q. Which of the following statements is true regarding exothermic reactions? (2021)
A.
They absorb heat.
B.
They release heat.
C.
They require energy input.
D.
They have a positive enthalpy change.
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Solution
Exothermic reactions release heat, resulting in a negative enthalpy change.
Correct Answer: B — They release heat.
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Q. Which of the following statements is true regarding ideal gases? (2023)
A.
They have no volume
B.
They attract each other
C.
They occupy no space
D.
They have mass
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Solution
Ideal gases are considered to have no volume and no intermolecular forces.
Correct Answer: A — They have no volume
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Q. Which of the following statements is true regarding the Arrhenius equation? (2023)
A.
It relates temperature to the rate constant
B.
It is only applicable to zero-order reactions
C.
It does not include activation energy
D.
It is a linear equation
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Solution
The Arrhenius equation relates temperature to the rate constant and includes activation energy.
Correct Answer: A — It relates temperature to the rate constant
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Q. Which of the following statements is true regarding the boiling points of aldehydes and ketones? (2023)
A.
Aldehydes have higher boiling points than ketones
B.
Ketones have higher boiling points than aldehydes
C.
Both have the same boiling points
D.
None of the above
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Solution
Ketones generally have higher boiling points than aldehydes due to stronger dipole-dipole interactions.
Correct Answer: B — Ketones have higher boiling points than aldehydes
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