Electrolysis

Chemistry

Topic: Electrolysis

What is it? 

Electrolysis uses an electricity to break down ionic compounds to form element, both reduction and oxidation takes place, so electrolysis is a redox reaction, during the reaction metals and gases my form on the electrode.

Ionic substances from when a metal reacts with a non-metal, for example sodium chloride forms when sodium reacts with a chlorine. It contains the positively charged sodium ions and the negatively charged chlorine ions.

Keywords:

-Electrode:

They are commonly made from inert materials, such as graphite and platinum, they are used to attract the cations and anions.

-Cathode:

The negatively charged 

electrode, it attracts positive ions (cations).

-Anode: 

The positively charged electrodes, it attracts negative ions (anions).

What is oxidation and reduction?

Reduction. When positively charged ions move to the negative electrode during the electrolysis. They receive electrons.

Oxidation: When the negatively charged ions move to the positive electrode during the electrolysis. They lose electrons.

How does electrolysis happen?

For electrolysis to work, the ions have to be able to move. The ions in the ionic substance are free to move when it is dissolved in water. For example if you're doing an electrolysis of CuSO4 in water.

-Cu has  a positive charge of +3.

-SO4 has  a negative charge of -2.

-OH has a negative charge of -1.

-H has a positive charge of +1.

The positive ions  (cations) will go to the cathode, while the negative ions (anions) will go to the anode. So, the copper and hydrogen will go to the cathode, while the hydroxide and sulphate will go to the anode.

What happens in the anode:

The more reactive element will stay in the solution, while the less reactive will return to its original form. So, hydrogen is more reactive than copper, the hydrogen will stay in the liquid, while the copper will return to its original from which is solid, the copper will start appearing on the anode.

What happens in the cathode:

The more reactive will stay in the solution, while the less reactive will return to its original form. So, hydroxide is more reactive than sulphate, the hydroxide will stay in the solution, while the sulphate will return to its original form, which is oxygen gas.

An easier way to remember oxidation and reduction?

Oxidation

Is

Loss

Reduction

Is

Gain

What is REDOX?

It is a reaction when both reduction and oxidation happens at the same time.

My group’s experiment:

In my group I did an experiment about electrolysis in LiCl solution.

Lab setup:

So we need 2 pencils, 2 wires and a power supply.

Elements present:

Li – Lithium

Cl – Chlorine

H – Hydrogen

OH – Hydroxide

What happens in the anode and cathode?

-Cathode (-):

The lithium and hydrogen will go to the cathode because they both are positive charged, and they are attracted to the negatively charged electrode, which is the cathode. Lithium is more reactive, so it stay, but hydrogen is less creative, so hydrogen will turn into its original form which is gas, and so hydrogen gas is produced.

-Anode (+):

The chlorine and hydroxide will go to the anode, the chlorine and hydroxide are negatively charged so they will go to the positive charged, which is the anode. OH is more reactive, so it stays  in the solution, but chlorine is less reactive, so chlorine will become its original form, which is gas, which means chlorine gas is produced.