Unit 7: Redox Reactions and Electrochemistry — Online MCQ Test
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Practice Unit 7: Redox Reactions and Electrochemistry with a free chapter-wise online MCQ test.
This chapter covers: Electronic concepts of oxidation and reduction redox reactions oxidation number rules for assigning oxidation number balancing of redox reactions. Electrolytic and metallic conduct....
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Unit 7: Redox Reactions and Electrochemistry — Important Questions & Answers
What is the change in oxidation number of carbon in the following reaction? CH4(g) + 4Cl2(g) -> CCl4(l) + 4HCl(g)
- A. 0 to +4
- B. -4 to +4
- C. 0 to -4
- D. +4 to +4
Answer: B. -4 to +4
In CH4, C is in -4 oxidation state. In CCl4, C is in +4 oxidation state.
In CH4, C is in -4 oxidation state. In CCl4, C is in +4 oxidation state.
On electrolysis of dil. sulphuric acid using Platinum (Pt) electrode, the product obtained at anode will be:
- A. Oxygen gas
- B. H2S gas
- C. SO2 gas
- D. Hydrogen gas
Answer: A. Oxygen gas
During electrolysis of dilute sulfuric acid, hydroxyl ions (OH-) or water molecules are discharged at the anode to produce oxygen gas.
During electrolysis of dilute sulfuric acid, hydroxyl ions (OH-) or water molecules are discharged at the anode to produce oxygen gas.
If the molar conductivity (Λm) of a 0.050 mol L⁻¹ solution of a monobasic weak acid is 90 S cm² mol⁻¹, its extent (degree) of dissociation will be [Assume Λ°+ = 349.6 S cm² mol⁻¹ and Λ°– = 50.4 S cm² mol⁻¹]
- A. 0.115
- B. 0.125
- C. 0.225
- D. 0.215
Answer: C. 0.225
Degree of dissociation α = Λm / Λ°m. Λ°m = 349.6 + 50.4 = 400. α = 90 / 400 = 0.225.
Degree of dissociation α = Λm / Λ°m. Λ°m = 349.6 + 50.4 = 400. α = 90 / 400 = 0.225.
If the molar conductivity (Λm) of a 0.050 mol L⁻¹ solution of a monobasic weak acid is 90 S cm² mol⁻¹, its extent (degree) of dissociation will be [Assume Λ⁰₊ = 349.6 S cm² mol⁻¹ and Λ⁰₋ = 50.4 S cm² mol⁻¹]
- A. 0.115
- B. 0.125
- C. 0.225
- D. 0.215
Answer: C. 0.225
Degree of dissociation α = Λm / Λ⁰m. Λ⁰m = Λ⁰₊ + Λ⁰₋ = 349.6 + 50.4 = 400. α = 90 / 400 = 0.225.
Degree of dissociation α = Λm / Λ⁰m. Λ⁰m = Λ⁰₊ + Λ⁰₋ = 349.6 + 50.4 = 400. α = 90 / 400 = 0.225.
Among the following the correct order of acidity is :
- A. HClO < HClO2 < HClO3 < HClO4
- B. HClO4 < HClO < HClO3 < HClO4
- C. HClO4 < HClO2 < HClO < HClO3
- D. HClO3 < HClO4 < HClO2 < HClO
Answer: A. HClO < HClO2 < HClO3 < HClO4
Acidity of oxyacids increases with the oxidation state of the central atom. The O.S. of Cl increases from +1 in HClO to +7 in HClO4.
Acidity of oxyacids increases with the oxidation state of the central atom. The O.S. of Cl increases from +1 in HClO to +7 in HClO4.