SG O Level Redox Reactions (basic)

What is the oxidation state of chlorine in sodium hypochlorite, NaClO (bleach)? [for Pure Chem only]

• -1

• +1

• -2

• +2

What is the oxidation state of oxygen in hydrogen peroxide, H₂O₂?

• +2

• -2

• +1

• -1

Which of the following is not a redox reaction?

• Displacement

• Neutralisation

• Rusting of iron

• Metal + acid reaction

When zinc reacts with hydrochloric acid, which substance is the reducing agent?

When sulfur dioxide was added into a solution, the solution turned from purple to colourless. What is the solution?

• Acidified potassium manga (VII)

• Acidified potassium manganate (VI)

• Acidified potassium iodide

• Acidified potassium manganate (VII)

• Cu is oxidised, as the oxidation state of Cu in CuSO₄ decreases from +2 to 0 in Cu.

• CuSO₄ is oxidised, as the oxidation state of Cu in CuSO₄ increases from 0 to +2 in Cu.

• Fe is oxidised, as the oxidation state of Fe increases from 0 to +2 in in FeSO₄

• Fe is oxidised, as the oxidation state of Fe increases from 0 to +3 in in FeSO₄

• AgNO₃ is reduced, as the oxidation of Ag in AgNO₃ decreases from +1 to 0 in Ag.

• Ag is reduced, as the oxidation of Ag in AgNO₃ decreases from +2 to 0 in Ag.

• Cu is reduced, as the oxidation of Cu decreases from +2 to 0 in Cu(NO₃)_2.

• Cu is reduced, as the oxidation of Cu decreases from 0 to -2 in Cu(NO₃)_2.

Which reaction is not a redox reaction?

When chlorine gas was passed into aqueous potassium iodide. What was the colour change of the solution?

• no colour change

• colourless to yellowish-brown

• yellowish-brown to colourless

• colourless to purple

What is the chemical formula of manganate (VII) ion?

• MnO₄^-

• MnO₄^2-

• Mn²⁺

• MnO^-