CHEMISTRY QUIZ F5 : CHAPTER 3

Oxidation reaction involves:

• gain in oxygen

• loss of oxygen

• gain of hydrogen

• loss of hydrogen

• loss of electrons

Reduction reaction involves ...............of oxygen.

The following chemical equation represents a redox reaction.

4Na + O₂ --> 2Na₂O

Which statement is true?

• Oxygen is oxidized

• Oxygen loses electron

• Sodium is an oxidising agent

• The oxidation number of sodium increases

What is the oxidation number of Y in Y₂O₃^2– ion?

• +2

• -2

• +4

• -4

Which equation represents a redox reaction?

• 2Cu + O₂ ---> 2CuO

• 2H⁺ + 2e ---> H₂

• Zn ---> Zn ²⁺ + 2e

• NaOH + HCl ---> NaOH + H₂O

Diagram shows a set-up of apparatus of a redox reaction.

Which of these statements are correct?

I Electron flows from electrode P to Q

II Iodide ion acts as reducing agent

III Manganate(VII) ion lose electrons to form manganese(II) ion

IV Acidified potassium manganate(VII) solution turns from purple to colourless

• I and III

• II and IV

• I, II and III

• I, II and IV

The following equation shows a redox reaction.

H₂S(g) + Cl₂(g) → S(s) + 2HCl(g)

Which of the following statements correctly describes the redox reaction?

• HCl gains hydrogen therefore it undergoes oxidation

• H₂S loses its hydrogen and undergoes reduction

• Chlorine gas, Cl₂, is an oxidizing agent

• Sulphur is a reducing agent

The following equation shows the redox reaction between copper and silver nitrate solution.

Which of the following statement is true about this reaction?

• Silver ion is oxidized

• Copper is the oxidizing agent

• The oxidation number of copper increases

• The oxidation number of nitrogen decreases

Diagram shows the apparatus set-up for a displacement reaction.

Based on diagram, what is the role of copper (II) sulphate solution?

• Hydrating agent

• Dehydrating agent

• Oxidising agent

• Reducing agent

The following equations represent some displacement reactions of metals.

X + Y sulphate ---> Y + X sulphate

X + Z sulphate ---> Z + X sulphate

Y + Z sulphate ---> no reaction.

The arrangement of metals X, Y and Z in ascending order of reactivity is

• X, Z, Y

• Y, Z, X

• Z, X, Y

• Z, Y, X