Conduction of Electricity in Liquids

How does electricity conduct in liquids? We know that under solids metals are the best electricity conductors. That is due to loosely held outermost mobile electrons that move from one atom to another. On the contrary, electrons in a chemical bond of liquids are static. Charges introduced by dissolving compounds in the water are responsible for the conduction of electricity in liquids. In water, the chemical bond of compound breaks into numerous atoms carrying a positive or negative charge on it. Freely moving charges flow resulting in electrical conductivity.

Electrolysis or How do Liquids Conduct Electricity?

The phenomena of chemical decomposition of liquid or solution constituting ions when electricity passed through it are called electrolysis. The compounds which break its chemical bond in water are called Ionic compounds. Are you thinking of an example; Sodium Chloride is an excellent example of an ionic compound. Atoms carrying charges are called Ions. Positive charge-carrying ion is called cations. Negative charge-carrying ions are called anions. Now if you mix Sodium Chloride in water, freely moving ions are formed. Cations travel to a negative electrode to collect electrons. Anions navigate to the positive electrode and donate its extra electrons.

If you have a query in your mind - what happens when electricity passes compounds in the molten state, then here is the answer – molten metal compound splits into single component form and gets accumulated at electrodes. Gases released as the result of this chemical reaction dissipates in the air. Now let’s move ahead and understand what happens when electricity passes in water.

Now let’s move ahead to understand what happens when electricity passes in water.

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Image of electrolysis of water displaying split of water in hydrogen and hydroxide ion moving towards cathode and anode respectively to release hydrogen and oxygen gas.

Electrolysis in Water

Let’s observe how electrolysis of water happens. The water dissociated into hydrogen and oxygen gas when the electric current passed through it. An electronic source connected to an inactive electrode like platinum immersed in water. Does pure water conduct electricity? Pure water is the best insulator. Therefore, an electrolyte was added to improve the conductivity of pure water. When electric power passes, the water separates into positive hydrogen ions and negatively charged hydroxide ions. Now, what happens to the charged ions?

H₂O = 2H⁺ + OH⁻

The two charged ions traverse towards opposite electrodes. Electron transfer from a negatively charged electrode, i.e. cathode to hydrogen ion leading to a reduction of the cathode. Whereas the positively charged electrode, i.e. anode gains an electron from hydroxide ion resulting in oxidation of anode.

Reduction at Cathode

The hydrogen ions move towards the cathode. These positive cations gain an electron from the cathode and convert into stable hydrogen gas.

H₂O = 2H⁺ + OH⁻

2 H⁺(aq)+ 2e⁻ → H₂(g)

Oxidation at Anode

Whereas, the negative hydroxide anion moves towards the anode. This negative anion loses an excess electron to the electrode and converts into stable oxygen gas.

4 H₂O → 4 OH⁻(aq) + 4 H⁺

4 OH⁻ (aq) → O₂ (g) + 2 H₂O (l) + 4 e

The ratio of generated oxygen and hydrogen molecules is 2:1. The electrolysis of water produces one molecule of oxygen for every two molecules of hydrogen. Thus twice the volume of hydrogen is generated as a result of water electrolysis. 

Testing the electrical conductivity of liquids can be done by the same mechanism. Take a fluid in a container which has two electrodes connected to battery and bulb. The glowing bulb will indicate that fluid is a good conductor of electricity.

Benefits of Electrolysis

Generation hydrogen for fuel, or the production of electric power using fuel cells 

• Production caustic soda from the concentrated saline solution.

• One of the most critical uses of electrolysis is the production of heavy metals like aluminium, sodium, calcium. During the electrolysis of molten compounds, heavy metals get precipitated at the electrode. Precipitated metal is collected and used for different industrial purposes.

• Another important use of electrolysis is the coating of one metal over another. The method used to coat a metal over another is called electroplating. The object to be coated with metal is used as a cathode. The anode is made of metal used for coating. The electrolyte is the soluble compound of metal to be coated.

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Image of the basic setup of electroplating to coat spoon which is made as cathode ,whereas anode is made of the metal which is used for coating.

Fascinating and Fun Fact with Regards Conduction of Electricity in Liquids

• Have you got skin with plenty of hair? Then visit beauty shops and get rid of extra hairs. Experts often use electrolysis to remove hair.

• Did you know that gold jewellery is made? Solid gold electrolyzed to make jewellery.

• Stainless steel cutleries in our kitchen like the spoon, fork, etc. are coated with copper by the process of electrolysis.

• Utensils used in the religious places is electroplated to convert into expensive silver utensils.