Electrolysis Preferential Discharge

Electrolysis Preferential Discharge 1

Position in Electrochemical Series

By Marsha Grant-Gibson

Multiple Choice

What ions are present in aqueous sulphuric acid, H₂SO_4(aq) ?

i. H⁺_(aq)

ii. H_2(g)

iii. SO₄^2-_(aq)

iv. OH^-_(aq)

• i and iii only.

• ii and iii only

• i, iii and iv only

• i, ii, iii and iv

Multiple Choice

Use the electrochemical series to predict which ion would be preferentially discharged at the cathode?

• K⁺

• Ag⁺

• H⁺

• Al³⁺

Multiple Choice

Which ion would be preferentially discharged at the anode?

• H⁺

• Ag⁺

• SO₄^2-

• OH^-

Multiple Choice

In the electrolysis of Magnesium sulphate solution, which ions would be attracted to the cathode?

i. Mg²⁺

ii. H⁺

iii. OH^-

iv. SO₄^2-

• i and ii only.

• ii only

• i and iv only

• ii and iii only

Multiple Choice

For the electrolysis of zinc chloride solution, identify the cation that would be preferentially discharged.

• Zn²⁺

• H⁺

• OH^-

• Cl^-

Multiple Choice

For the electrolysis of copper sulphate solution, identify the observation made at the cathode.

• Effervescence, gas evolved that outs a lit splint with a pop

• Effervescence, gas evolved that relights a glowing splint

• silver grey solid deposited

• Salmon/brown solid deposited

Multiple Choice

For the electrolysis of zinc chloride solution, identify the anion that would be preferentially discharged.

• Zn²⁺

• H⁺

• OH^-

• Cl^-

Multiple Choice

For the electrolysis of copper sulphate solution, identify the observation made at the anode.

• Effervescence, gas evolved that outs a lit splint with a pop

• Effervescence, gas evolved that relights a glowing splint

• silver grey solid deposited

• Pungent gas evolved

Multiple Choice

Identify the electrolyte that would give the following observation at the cathode.

'Silver coloured solid deposited'.

• Magnesium chloride solution

• sodium hydroxide solution

• Platinum nitrate solution

• sulphuric acid

Multiple Choice

Identify the electrolyte that would give the following observation at the cathode.

'Effervescence, colourless gas evolved which outs a burning splint with a pop'.

• Potassium bromide solution

• gold nitrate solution

• Platinum nitrate solution

• mercury nitrate solution

Multiple Choice

Identify the electrolyte that would give the following observation at the anode.

'red brown solution/fumes evolved'.

• Potassium bromide solution

• copper nitrate solution

• molten zinc bromide

• molten Lead iodide