Electrochemistry - Electrolysis

An electrolytic cell uses electrical energy to drive

• chemical reaction

• physical reaction

• no reaction

• none of above

Galvanic cells convert

• mechanical energy in to electrical energy

• potential energy in to electrical energy

• electrical energy in to chemical energy

• chemical energy in to electrical energy

When water is electrolyzed, gas collected at cathode, is

• sulphur

• oxygen

• hydrogen

• sulphur dioxide

In electrolysis, particles which move towards cathode are called

• anions

• cations

• photons

• positrons

Diagram shows an electrolytic cell.

Which of the substances cause the bulb to light up when electricity passes through it?

• Ethanol

• Dilute ethanoic acid

• Solid lead(II) bromide

• Tetrachloromethane

What are the products formed at the anode and the cathode during the electrolysis of molten magnesium oxide using carbon electrodes?

• Anode: Oxygen

  Cathode: Magnesium

• Anode: Magnesium

  Cathode: Oxygen

• Anode: Hydrogen

  Cathode: Oxygen

• Anode: Oxygen

  Cathode: Hydrogen

Diagram shows the electrolysis of concentrated copper(II) chloride solution using carbon as electrodes.

Which of the followings is the correct half equations represents the reactions at the anode?

• 4OH^- → 2H₂O + O₂ + 4e

• 2Cl^- → Cl₂ + 2e

• Cu → Cu²⁺ + 2e

• Cu²⁺ + 2e → Cu

Diagram

shows the apparatus set-up for the electrolysis of 2.0 mol dm ^-3 sodium chloride solution using carbon electrodes.Which of the following are the observation for the electrolysis process shown in Diagram?

• Grey solid deposited on electrode B

• Colourless gas is released at electrode B

• Carbon electrode A becomes thinner

• Greenish yellow gas is released at electrode A

Molten X is electrolysed using carbon electrodes. After 10 minutes, a brown solid is deposited on the cathode and a brown gas is released at the anode. What is molten X?

• Lead(II) chloride

• Lead(II) bromide

• Copper(II) chloride

• Copper(II) bromide

Table shows the results of the electrolysis of molten lead (II) bromide.

The ammeter only shows reading when solid lead (II) bromide, PbBr₂ is completely melted. Which of the following explains the observation?

• Bromide ions receive electrons to form bromine gas

• Lead (II) ions donate electrons to produce lead metal

• In the solid state, bromide and lead (II) ions are held in a lattice

• Electrical conductivity occurs throughout

  the whole experiment