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1800-102-2727Have you ever wondered why salt solution conducts electricity and we never talk about the conductivity of sugar solution?
Both are chemicals used in our everyday life so frequently but their behaviour is like the south and north pole. So, Faradays is the one who unfolds the reason behind it. He distinguished between a salt solution and a sugar solution and divided substances into two groups: electrolytes and non-electrolytes.
Table of contents
When electrolytes are dissolved in water, they dissociate into ions and conduct electricity. In water, electrolytes produce oppositely charged ions.
Some electrolytes are ionic compounds and hence made up of oppositely charged ions, The electrostatically bound ions get dissociated in water and hydrated by water molecules. Because of the charged ions, they can conduct electrical current not only in an aqueous state but also in a molten state. Example: Acids, bases, and salts.
Some polar covalent molecules can react with water to form cations and anions and conduct electricity in an aqueous state only.
Ion-dipole attractions between the dissociated ions and the polar water molecules aid in the solubility of the compound increased concentration of ions and electrical conductivity.
There are two types of electrolytes. Strong electrolytes and weak electrolytes can be distinguished as follows:
Strong electrolytes are soluble ionic compounds and strong acids that ionize entirely, whereas weak acids and bases ionize to a lesser amount and are Weak electrolytes.
Strong Electrolytes |
Weak Electrolytes |
They dissociate almost completely in their aqueous solutions. |
They dissociate partially in their aqueous solutions. |
Strong acids (HCl, H2SO4etc.) |
Weak acids (CH3COOH, H2C2O4etc.) |
Strong bases (NaOH, KOH etc.) |
Weak bases (Ca(OH)2, C5H5N etc.) |
Example: All soluble salts (NaCl, CH3COONa etc.) |
Example: All sparingly soluble salts (AgCl, BaSO4 etc.) |
Sparingly soluble salts are the ones that have lower solubility.
As strong electrolytes are completely ionized in the aqueous solution, their ionization is represented by putting a single arrow pointing towards the right
Example:
In the case of weak electrolytes, as they are partially ionized, the ionized ions have the tendency to
recombine with the unionized electrolyte.
Therefore, an equilibrium is set up between the ions and the unionized electrolyte. Hence, their
ionization is represented by putting double half arrows (⇌).
Example: CH3COOH(aq) ⇌ CH3COO-(aq)+H+(aq)
NH4OH(aq) ⇌ NH4+(aq)+OH-(aq)
Therefore, ionic equilibrium is seen in weak electrolytes. The behaviour of weak electrolytes can be studied using the law of equilibrium.
A non-electrolyte is a material that does not conduct electricity in its aqueous solution. When compounds are dissolved in water, nonelectrolytes do not create ions.
Examples: Sugar, urea, glucose, etc.
It is known that the aqueous solution of sugar does not conduct electricity. This is because sugar is a pure covalent compound and does not dissociate into ions, though the whole molecule forms strong hydrogen bonds with water.
In general, the ionization of a weak electrolyte, AB, is represented as follows:
AB(aq) ⇌ A+ (aq)+B-(aq)
Such an equilibrium is known as an ionic equilibrium between the ions and the undissociated
electrolyte. Applying the law of chemical equilibrium to the given equilibrium, the Equilibrium constant in terms of concentration,
The fraction of the number of molecules of the electrolyte dissociated into ions at equilibrium out of the total number of molecules of the electrolyte dissolved is known as the degree of dissociation. It is represented by α.
For a weak electrolyte, α << 1
For a strong electrolyte, α ≈ 1
On dilution, the probability of interaction between the dissociated ions decreases. Thus, as the rate of backward reaction also decreases, increasing the rate of dissociation, which forms more ions, i.e., when the dilution increases, the extent of ionization also increases.
The degree of dissociation of an electrolyte at infinite dilution is assumed to be unity (α ≈ 1).
Q1. Which of the following is a Non - Electrolyte?
A. HCOOH
B. H2SO4
C. C6H12O6
D. SiF4
Answer (C)
C6H12O6 is the molecular formula of carbohydrates or monosaccharides, which are sugars. Sugar in an aqueous solution does not conduct electricity, as is widely known. Hence, option (C) is non-electrolyte.
Q2. Which among the given substances can be classified as non-electrolytes?
A. NaCl
B. Potassium hydroxide
C. Glucose
D. Calcium sulfate
Answer: (C)
Glucose is a natural sugar. Sugar in an aqueous solution does not conduct electricity, as is widely known. Because of the strong hydrogen connections created, the sugar does not break down into ions.
Q3. All electrolyte solutions have one thing in common:
A. always contain acids or bases
B. contain molecules
C. conduct electricity
D. react with other solutions
Answer: (C)
As per the definition of electrolytes, they are those substances that conduct electricity. Option (C) is the best option among all which can distinguish electrolytes.
Q4. Diamonds are considered nonelectrolytes. What does this mean?
A. They have low viscosity
B. They are insoluble in inorganic solvents
C. They have high-density
D. They do not conduct electricity
Answer : (D)
Non-electrolytes are those substances that do not conduct electricity. So, diamonds are the ones that do not conduct electricity. Hence option (D) is correct. Non-electrolytes are not related to viscosity, insolubility, and density.
Question 1. What is the difference between dissociation and ionization?
Answer: When the ionic compound is dissolved, ions already present in the solid solution separate out. This is dissociation. When a neutral or covalent compound is dissolved, it dissociates into ions in the solution. This is ionization.
Question 2. Why electrolytes are important to study?
Answer: Electrolytes are electrically charged particles that are made up of substances found in body fluids (ions). These ions store the electrical energy required for a variety of tasks, including muscle contractions and nerve impulse transmission.
Question 3. Is water a strong electrolyte?
Answer: If it is pure water, which has a very low ion content, it can't conduct electricity. Hence, pure water is a weak electrolyte. When a substance dissociates to form ions in water, it is called a strong electrolyte. Hence, in solution form, water acts as strong electrolytes.
Question 4. Is aqueous carbon dioxide conduct electricity?
Answer: CO2 gas, when dissolved in water, produces a solution containing hydrogen ions, carbonate, and hydrogen carbonate ions:
The resulting solution will conduct electricity since it contains ions. However, because CO2does not dissolve into ions, it is vital to remember that it is not an electrolyte. Electrolytes are substances that break down into their component ions in solution.
Question 5. Is CaCO3, an insoluble ionic compound, an electrolyte or a non-electrolyte?
Answer: CaCO3 being an ionic compound will conduct electricity but as they are insoluble in water, hence not able to dissociate into ions. Hence, they are non-electrolytes
Related Topics
Acids Bases and Salt |
Lewis concept |
Lowry Bronsted theory |
Ionic product of water |
Arrhenius theory |