Chapter 6 Chemistry form 4

1.Solid lead(II) bromide does not conduct electricity because

• It consists of molecules

• It does not contain ion.

• It contains lead(II) ions and bromide ions that are not

  free to move.

• Lead(II) ions and bromide ions are bonded by strong

  covalent bonds.

When aqueous copper(II) chloride solution is electrolysed using copper electrodes, the half-equation for the reaction that occurs at the anode is

• Cu²⁺ + 2e -------> Cu

• Cu --------> Cu²⁺ + 2e

• 2Cl^- --------> Cl₂ + 2e

• 4OH^- --------> 2H₂O + O₂ + 4e

At which electrodes are Group 17 elements produced?

Pada elektrod manakah unsur Kumpulan 17 dihasilkan?

• A E and G

  E dan G

• B F and H

  F dan H

• C E and F

  E dan F

• D F and G

  F dan G

Diagram 12 shows an apparatus used to electroplate a metal ring with copper.

The experiment did not work.

What change is needed to make the experiment work?

• Add solid copper(II) sulphate to the electrolyte

• Increase the temperature of the electrolyte

• Replace the copper electrode by a carbon electrode

• Reverse the connections to the battery

Diagram 18 shows the apparatus set-up for electrolysis of 1.0 mol dm^-3 copper(II) nitrate solution using copper electrodes.

Which of the following are observation at the anode and cathode?

• Electrode become thinner at anode and Brown solid deposited at cathode

• Electrode become thinner at anode and Colourless gas released at cathode

• Greenish yellow gas released at anode and brown solid deposited at cathode

• Colourless gas released at anode and Colourless gas released at cathode

Diagram 11 shows the apparatus set-up to purify an impure silver plate.

4.0 g of impure silver plate dissolved while 3.8 g of silver deposited at the pure silver plate

What is the percentage of purity of the impure silver plate?

• 5.0 %

• 5.3 %

• 51.3 %

• 95.0 %

Diagram 3 shows the electrolysis of copper(II) sulphate solution using platinum electrodes.

Which ion is discharged at anode?

• Copper(II) ion

• Hydrogen ion

• Sulphate ion

• Hydroxide ion

What are the cations present in zinc sulphate solution?

• Zn²⁺

• Zn²⁺, SO₄²

• Zn²⁺ , H⁺

• OH^- , SO₄^2-

Diagram 23 shows an electrolytic circuit using inert electrodes.

At which electrode is metal deposited?

• A

• B

• C

• D

The figure shows the apparatus set up for electrolysis of copper(II) sulphate solution using carbon electrodes.

Which of the following are true about the electrolysis?

i Brown deposit is formed at the cathode

ii Intensity of the blue solution decreases

iii Bubbles of greenish yellow gas is evolved at the anode

iv Size of both electrodes increase

• I and II

• II and III

• II and IV

• I, III and IV