Strong Electrolytes and Weak Electrolytes

Strong Electrolytes are compounds that completely dissociate into their ions when dissolved in water. Whereas Weak Electrolytes are compounds that partially dissociate into their ions when dissolved in water.

In this article, we will learn about, What is Electrolytes, Examples of Weak and Strong Electrolytes, and others in detail.

What is Electrolytes?

Electrolytes are the substance that dissociates its ions when dissolved in water (aqueous solution), completely or partially. The positively charged ions present are called cations. The negatively charged ions present are called anions. Some examples of electrolytes are Sodium Chloride(NaCl), Hydrochloric Acid(HCl), Sodium Hydroxide(NaOH), etc.

Types of Electrolytes

There are two types of Electrolytes that are,

• Strong Electrolytes
• Weak Electrolytes

Strong Electrolytes Definition

Strong Electrolytes are those compounds which completely dissociates into positive and negative ions when dissolved in water.

• These Electrolytes completely ionized in water.
• In solution or molten form , these electrolytes are ionized completely.
• At high concentrations, there are strong interionic interactions.
• Due to complete dissociation in aqueous solution, these Electrolytes are good Conductor of Electricity.
• Ostwald’s dilution law is not applicable.

Examples of Strong Electrolytes

Some Categories of Strong Electrolytes are mentioned below :

Strong Acid

Strong acids completely dissociates in aqueous solution and are good conductor of electricity. Some strong acids are Hydrochloric Acid(HCl), Sulphuric Acid(H₂SO₄), Nitric Acid(HNO₃) etc.

Strong Base

Like Strong acid Strong bases also dissociates completely in aqueous solution and are good conductors of Electricity. Some Strong bases are Sodium Hydroxide(NaOH), Potassium Hydroxide(KOH), Lithium Hydroxide(LiOH) etc.

Salt

Salt which is made of combination of Strong acids and Strong Bases, or with Strong acid and Weak Base, or with Weak acid and Strong Bases falls in category of Strong electrolytes. These are good conductors of Electricity. Some examples of Salt are Sodium Chloride(NaCl), Sodium Bromide(NaBr), Potassium Bromide(KBr) etc.

Characteristic of Strong Electrolyte

• Even in small quantity Strong Electrolytes conduct electricity.
• Characteristic of Strong Electrolyte depends on number of parameters such as size of the ion, concentration of ion etc.

Weak Electrolyte Definition

Weak Electrolytes are those compounds which partially dissociates into positive and negative ions when dissolved in water.

• These Electrolytes are partially dissolved in water.
• In solution or molten form, these electrolytes are partially ionized.
• Even at higher concentration, interionic interactions are weak.
• Due to partial dissociation in aqueous solution, these electrolytes are bad conductor of electricity.
• Ostwald’s dilution law is applicable on weak electrolytes.

Examples of Weak Electrolytes

Some Categories of Weak Electrolytes are mentioned below :

Weak Acid

Weak Acid dissociates partially in water and are bad conductor of Electricity, so these are weak electrolytes. Some examples of weak acid are Hydrofluoric Acid (HF), Acetic Acid (CH₃COOH), Carbonic Acid (H₂CO₃).

Weak Base

Weak bases partially dissociates in water and are bad conductor of Electricity, so these are weak electrolytes. Some Example of Weak Bases are Aluminium Hydroxide (Al(OH)₃), Ammonia (NH₃) etc.

Characteristic of Weak Electrolytes

• At moderate concentrations, weak electrolytes do not dissociate completely.
• Characteristic of Strong Electrolyte depends on number of parameters such as size of the ion, concentration of ion etc.

Difference between Strong and Weak Electrolyte

The difference between Strong and Weak Electrolyte are tabulated below:

Basis of Comparison	Strong Electrolyte	Weak Electrolyte
Dissociation in aqueous Solution	Completely	Partially
Electrical Conductivity	High	Low
Ostwald’s dilution law	Applicable	Not Applicable
interionic interaction	Strong	Weak
in Solution or Molten form	Completely ionized	Partially ionized
Examples	Strong Acid, Strong Base and salt	Weak Acid and Weak Base

Strong and Weak Electrolytes – FAQs

1. Define Non-Electrolytes.

A nonelectrolyte is a compound that does not conduct an electric current in either aqueous solution or in the molten state.

2. What are Electrolytes Present in Human Body?

Calcium (Ca²⁺), sodium (Na⁺), and potassium (K⁺), for example, are required for muscular contraction. Muscular weakness or strong muscle spasms might develop if these important electrolytes are not present in sufficient amounts.

3. What is Ostwald’s Dilution Law?

According to Ostwald’s Dilution Law the degree of dissociation of a weak electrolyte is inversely proportional to the square root of molar concentration or directly proportional to the square root of volume holding one mole of the solute for a weak electrolyte.

4. Is a NaOH a Strong Electrolyte?

Yes, Sodium Hydroxide (NaOH) is a strong electrolyte.

5. What are 4 Weak Electrolytes?

4 Weak Electrolytes are,

• Acetic Acid
• Zinc Hydroxide
• Carbonic Acid
• Ammonium Hydroxide

6. Is NaCl a Weak Electrolyte?

No, NaCl is a strong electrolyte, because NaCl is easily dissolved in water giving, Na⁺ ion and Cl^– ion.