Chemistry
Q. In the reaction 2Mg + O2 → 2MgO, which element is oxidized? (2021)
A.
Magnesium
B.
Oxygen
C.
Both Magnesium and Oxygen
D.
Neither Magnesium nor Oxygen
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Solution
Magnesium is oxidized as it loses electrons and its oxidation state increases from 0 to +2.
Correct Answer: A — Magnesium
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Q. In the reaction 3H2 + N2 → 2NH3, which element is reduced? (2022)
A.
H2
B.
N2
C.
NH3
D.
None
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Solution
N2 is reduced to NH3 as it gains electrons.
Correct Answer: B — N2
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Q. In the reaction 4Fe + 3O2 → 2Fe2O3, which element is oxidized?
A.
Fe
B.
O2
C.
Fe2O3
D.
None of the above
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Solution
Iron (Fe) is oxidized as it loses electrons to form Fe2O3.
Correct Answer: A — Fe
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Q. In the reaction Zn + CuSO4 → ZnSO4 + Cu, which species is reduced?
A.
Zn
B.
CuSO4
C.
ZnSO4
D.
Cu
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Solution
Copper (Cu) is reduced as it gains electrons from zinc.
Correct Answer: D — Cu
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Q. In the redox reaction 2Ag+ + Cu → 2Ag + Cu2+, which species is oxidized? (2022) 2022
A.
Ag+
B.
Cu
C.
Ag
D.
Cu2+
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Solution
Cu is oxidized to Cu2+ as it loses electrons in the reaction.
Correct Answer: B — Cu
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Q. In the redox reaction 2Ag+ + Zn → 2Ag + Zn2+, which species is oxidized? (2021)
A.
Ag+
B.
Zn
C.
Ag
D.
Zn2+
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Solution
Zn is oxidized to Zn2+ as it loses electrons.
Correct Answer: B — Zn
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Q. In the redox reaction 2MnO4- + 5C2O4^2- + 16H+ → 2Mn^2+ + 10CO2 + 8H2O, what is the oxidation state of carbon in C2O4^2-?
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Solution
In C2O4^2-, the oxidation state of carbon is +3.
Correct Answer: C — +4
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Q. In which of the following processes is adsorption utilized? (2023)
A.
Water purification
B.
Sublimation
C.
Distillation
D.
Filtration
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Solution
Adsorption is widely used in water purification processes to remove impurities.
Correct Answer: A — Water purification
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Q. In which state of matter do particles have the least amount of energy?
A.
Solid
B.
Liquid
C.
Gas
D.
Plasma
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Solution
Particles in a solid have the least amount of energy compared to liquids, gases, and plasma.
Correct Answer: A — Solid
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Q. In which state of matter do particles move freely and are far apart? (2021)
A.
Solid
B.
Liquid
C.
Gas
D.
None of the above
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Solution
In gases, particles move freely and are far apart compared to solids and liquids.
Correct Answer: C — Gas
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Q. The half-life of a first-order reaction is dependent on which of the following? (2020) 2020
A.
Initial concentration of reactants
B.
Rate constant
C.
Temperature
D.
All of the above
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Solution
The half-life of a first-order reaction is independent of the initial concentration and is directly proportional to the rate constant.
Correct Answer: B — Rate constant
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Q. The half-life of a first-order reaction is independent of the initial concentration of the reactant. What is the formula for the half-life (t1/2) of a first-order reaction? (2020)
A.
t1/2 = 0.693/k
B.
t1/2 = k/0.693
C.
t1/2 = 1/k
D.
t1/2 = k/1
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Solution
The half-life of a first-order reaction is given by the formula t1/2 = 0.693/k, where k is the rate constant.
Correct Answer: A — t1/2 = 0.693/k
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Q. The Langmuir isotherm assumes that adsorption occurs at specific sites on the surface. What does this imply? (2020)
A.
Adsorption is uniform.
B.
Adsorption is multilayered.
C.
Adsorption is monolayered.
D.
Adsorption is temperature dependent.
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Solution
The Langmuir isotherm assumes that adsorption occurs at specific sites, leading to a monolayer coverage of the adsorbate.
Correct Answer: C — Adsorption is monolayered.
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Q. The Langmuir isotherm assumes that adsorption occurs at specific sites on the surface. What is the maximum coverage called? (2021)
A.
Saturation
B.
Monolayer
C.
Multilayer
D.
Equilibrium
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Solution
In the Langmuir isotherm, the maximum coverage of adsorbate on the adsorbent is referred to as a monolayer.
Correct Answer: B — Monolayer
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Q. The rate constant of a reaction is affected by which of the following? (2023)
A.
Nature of the reactants
B.
Temperature
C.
Catalysts
D.
All of the above
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Solution
The rate constant of a reaction is affected by the nature of the reactants, temperature, and the presence of catalysts.
Correct Answer: D — All of the above
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Q. What does the term 'enthalpy' refer to? (2020)
A.
Internal energy plus pressure times volume
B.
Heat content of a system at constant pressure
C.
Total energy of a system
D.
Work done by the system
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Solution
Enthalpy refers to the heat content of a system at constant pressure, defined as internal energy plus pressure times volume.
Correct Answer: B — Heat content of a system at constant pressure
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Q. What happens to the entropy of an isolated system? (2020) 2020
A.
It decreases
B.
It remains constant
C.
It increases
D.
It can either increase or decrease
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Solution
According to the second law of thermodynamics, the entropy of an isolated system always increases over time.
Correct Answer: C — It increases
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Q. What happens to the pressure of a gas if the volume is decreased while the temperature remains constant?
A.
Increases
B.
Decreases
C.
Remains the same
D.
Doubles
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Solution
According to Boyle's Law, if the volume decreases and temperature is constant, the pressure increases.
Correct Answer: A — Increases
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Q. What happens to the temperature of a gas during an isothermal expansion? (2021)
A.
Increases
B.
Decreases
C.
Remains constant
D.
Varies with pressure
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Solution
During an isothermal expansion, the temperature of the gas remains constant as the system absorbs heat to do work.
Correct Answer: C — Remains constant
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Q. What happens to the volume of a gas when its temperature increases at constant pressure? (2020)
A.
Volume decreases
B.
Volume remains constant
C.
Volume increases
D.
Volume fluctuates
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Solution
According to Charles's Law, the volume of a gas increases with an increase in temperature at constant pressure.
Correct Answer: C — Volume increases
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Q. What is the atomic mass of Oxygen approximately? (2019)
A.
16 u
B.
18 u
C.
14 u
D.
12 u
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Solution
The atomic mass of Oxygen is approximately 16 u.
Correct Answer: A — 16 u
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Q. What is the atomic mass of Sodium (Na)? (2021)
A.
22.99
B.
23.00
C.
24.00
D.
25.00
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Solution
The atomic mass of Sodium (Na) is approximately 22.99 u.
Correct Answer: A — 22.99
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Q. What is the atomic number of Carbon? (2021)
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Solution
The atomic number of Carbon is 6, which is the number of protons in its nucleus.
Correct Answer: A — 6
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Q. What is the atomic number of Oxygen?
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Solution
The atomic number of Oxygen is 8.
Correct Answer: B — 8
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Q. What is the basic unit of proteins? (2023) 2023
A.
Monosaccharide
B.
Amino acid
C.
Nucleotide
D.
Fatty acid
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Solution
Proteins are made up of amino acids, which are their basic building blocks.
Correct Answer: B — Amino acid
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Q. What is the boiling point of water at standard atmospheric pressure?
A.
100°C
B.
0°C
C.
50°C
D.
150°C
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Solution
The boiling point of water at standard atmospheric pressure is 100°C.
Correct Answer: A — 100°C
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Q. What is the boiling point trend among alcohols? (2020) 2020
A.
Decreases with molecular weight
B.
Increases with molecular weight
C.
Remains constant
D.
Increases with branching
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Solution
The boiling point of alcohols increases with molecular weight due to stronger hydrogen bonding.
Correct Answer: B — Increases with molecular weight
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Q. What is the boiling point trend among primary, secondary, and tertiary amines?
A.
Primary > Secondary > Tertiary
B.
Tertiary > Secondary > Primary
C.
Secondary > Primary > Tertiary
D.
All have the same boiling point
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Solution
Primary amines have higher boiling points than secondary and tertiary amines due to stronger hydrogen bonding.
Correct Answer: A — Primary > Secondary > Tertiary
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Q. What is the boiling point trend of alcohols compared to alkanes?
A.
Higher
B.
Lower
C.
Same
D.
Varies
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Solution
Alcohols have higher boiling points than alkanes due to hydrogen bonding.
Correct Answer: A — Higher
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Q. What is the boiling point trend of amines compared to alkanes?
A.
Higher
B.
Lower
C.
Same
D.
Varies
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Solution
Amines have higher boiling points than alkanes due to hydrogen bonding.
Correct Answer: A — Higher
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