to clean the beaker

to clean up spilled electrolyte

to remove oxide layer on the electrode

to remove dust on the electrode

D, C, A, B

C, A, B, D

C, A, D, B

D, B, C, A

D, C, B, A

D, C, A, B

B, A, C, D

B, A, D, C

bubble gas evolved at the cathode

bubble gas evolved at the anode

carbon electrode becomes thicker

brown solid deposited at anode

The wires is not connected properly

The power button is switched on

The analytical balance is not functioning properly

The stopwatch stop ticking

The cathode electrode need to dry properly before the final mass is weighed

When running the electrolysis, both electrodes should not be in contact with each other.

The electrodes used should be cleaned with sand paper properly.

The electrodes need to immerse in the electrolyte fully.

II & IV

I, II, & III

I & III

All of the above

The electrolytic cell is set up using ammeter and power supply.

The electrolyte must be filled to 3/4 volume of the beaker

The time taken for the electrolysis should be recorded using a stopwatch

The electrode used at the cathode should be weighed immediately after the electrolysis is stopped

Clean up workplace after the experiment is done

If a hair dryer is used, make sure it was used at appropriate distance to the electrode

Put all used sand papers left in the dustbin

Pour back the electrolyte used in their original flask to avoid wasting

The wires are not connected properly

Both electrodes touch each other

Both electrodes are not immerse in the electrolyte

The negative terminal is connected to anode and the positive terminal is connected to cathode

To stabilize the reading

To reset the reading to zero display

To hold the mass of the substances displayed

To remove the weight of the door of the analytical balance.

The solid deposited at the bottom of the beaker is not collected

The analytical balance are closed while weighing.

The TARE button is not used.

The electrodes are weighed immediately after electrolysis stopped.

carbon electrode is connected to the positive terminal of the power supply

carbon electrode is connected to the negative terminal of the power supply

carbon electrode is connected to the ammeter

copper electrode is connected to the positive terminal of the power supply

If it is a small amount, we can ignore as the small amount will not affect the final mass.

Try to collect the solid using filter paper, dry and add the mass with the mass of the electrode.

Try to collect the solid using filter paper, if the mass does not exceed 0.5 g, we should ignore the mass.

Try to collect the solid using filter paper, dry and add the mass with mass of the electrode only if it weighs more than 0.5 g.

ii. iii and iv

i, iii and iv

iii and iv

All of the above

1

2

3

4