Redox Reactions MCQs with Answers

AdminJanuary 30, 2023

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Redox reactions involve the __________.
a) Transfer of electrons
b) Formation of covalent bonds
c) Dissociation of ions
d) Absorption of light
Answer: a) Transfer of electrons

Oxidation is the __________.
a) Gain of electrons
b) Loss of electrons
c) Formation of a compound
d) Increase in oxidation state
Answer: b) Loss of electrons

Reduction is the __________.
a) Gain of electrons
b) Loss of electrons
c) Formation of a compound
d) Increase in oxidation state
Answer: a) Gain of electrons

In a redox reaction, the substance that is oxidized is called the __________.
a) Oxidizing agent
b) Reducing agent
c) Catalyst
d) Product
Answer: b) Reducing agent

In a redox reaction, the substance that is reduced is called the __________.
a) Oxidizing agent
b) Reducing agent
c) Catalyst
d) Product
Answer: a) Oxidizing agent

Which of the following represents a redox reaction?
a) 2H2O → 2H2 + O2
b) NaCl + AgNO3 → NaNO3 + AgCl
c) NH3 + HCl → NH4Cl
d) H2SO4 → H2O + SO3
Answer: a) 2H2O → 2H2 + O2

Which element is undergoing reduction in the following reaction: Cl2 + 2Na → 2NaCl?
a) Chlorine (Cl)
b) Sodium (Na)
c) Oxygen (O)
d) Hydrogen (H)
Answer: a) Chlorine (Cl)

Which element is undergoing oxidation in the following reaction: Cl2 + 2Na → 2NaCl?
a) Chlorine (Cl)
b) Sodium (Na)
c) Oxygen (O)
d) Hydrogen (H)
Answer: b) Sodium (Na)

Which of the following is a redox reaction?
a) NaCl + H2O → NaOH + HCl
b) MgO + H2O → Mg(OH)2
c) CaCO3 → CaO + CO2
d) NH3 + HCl → NH4Cl
Answer: a) NaCl + H2O → NaOH + HCl

The oxidation state of an atom represents __________.
a) The number of protons in the nucleus
b) The number of neutrons in the nucleus
c) The number of electrons gained or lost
d) The mass of the atom
Answer: c) The number of electrons gained or lost

Which of the following represents a redox reaction?
a) 2H2O2 → 2H2O + O2
b) NaCl + KNO3 → NaNO3 + KCl
c) NH3 + H2O → NH4OH
d) CO2 + H2O → H2CO3
Answer: a) 2H2O2 → 2H2O + O2

In the reaction: Cu + 2AgNO3 → Cu(NO3)2 + 2Ag, which species is reduced?
a) Copper (Cu)
b) Silver (Ag)
c) Nitrate (NO3)
d) Water (H2O)
Answer: b) Silver (Ag)

In the reaction: 2Na + Cl2 → 2NaCl, which species is oxidized?
a) Sodium (Na)
b) Chlorine (Cl)
c) Sodium chloride (NaCl)
d) Water (H2O)
Answer: a) Sodium (Na)

The substance that gains electrons in a redox reaction is __________.
a) Reduced
b) Oxidized
c) Neutralized
d) Dissociated
Answer: a) Reduced

The substance that loses electrons in a redox reaction is __________.
a) Reduced
b) Oxidized
c) Neutralized
d) Dissociated
Answer: b) Oxidized

The oxidation state of an uncombined element is __________.
a) Zero
b) Positive
c) Negative
d) Equal to its atomic number
Answer: a) Zero

Which of the following reactions is a redox reaction?
a) HCl + NaOH → NaCl + H2O
b) CaO + CO2 → CaCO3
c) NH3 + HCl → NH4Cl
d) H2SO4 → H2O + SO3
Answer: d) H2SO4 → H2O + SO3

The oxidation number of hydrogen (H) in most compounds is __________.
a) +1
b) -1
c) 0
d) It varies depending on the compound
Answer: a) +1

The oxidation number of oxygen (O) in most compounds is __________.
a) +1
b) -1
c) 0
d) It varies depending on the compound
Answer: b) -1

Which of the following reactions is a redox reaction?
a) NaCl + H2O → NaOH + HCl
b) CaO + H2O → Ca(OH)2
c) CH4 + 2O2 → CO2 + 2H2O
d) NH3 + HCl → NH4Cl
Answer: c) CH4 + 2O2 → CO2 + 2H2O

The species that is oxidized in the reaction: Cl2 + 2Na → 2NaCl is __________.
a) Chlorine (Cl)
b) Sodium (Na)
c) Sodium chloride (NaCl)
d) Water (H2O)
Answer: a) Chlorine (Cl)

The species that is reduced in the reaction: Cl2 + 2Na → 2NaCl is __________.
a) Chlorine (Cl)
b) Sodium (Na)
c) Sodium chloride (NaCl)
d) Water (H2O)
Answer: b) Sodium (Na)

Which of the following reactions is a redox reaction?
a) H2O2 → H2O + O2
b) NaCl + KNO3 → NaNO3 + KCl
c) NH3 + H2O → NH4OH
d) CO2 + H2O → H2CO3
Answer: a) H2O2 → H2O + O2

The oxidation state of an atom in its elemental form is __________.
a) +1
b) -1
c) 0
d) Equal to its atomic number
Answer: c) 0

In the reaction: Cu + 2AgNO3 → Cu(NO3)2 + 2Ag, which species is oxidized?
a) Copper (Cu)
b) Silver (Ag)
c) Nitrate (NO3)
d) Water (H2O)
Answer: a) Copper (Cu)

In the reaction: Cl2 + 2Na → 2NaCl, which species is reduced?
a) Chlorine (Cl)
b) Sodium (Na)
c) Sodium chloride (NaCl)
d) Water (H2O)
Answer: a) Chlorine (Cl)