NCERT Activity 3.13 Class 10 Science Explanation

In this activity, we will explore the physical and chemical properties of ionic compounds.

 

Properties of Ionic Compounds

 

Aim of the activity

To study the physical and chemical properties of ionic compounds

Materials Required

   1. Samples of ionic compounds (NaCl , KI , BaCl₂)

   2. Metal spatula

   3. Spirit lamp

   4. Test tubes

   5. Beakers with water, petrol, kerosene

   6. Conductivity tester

Procedure

We will perform the following activities:

     1.  Physical state

  We observe each salt and note their physical state.

     2. Flame test

 We take a small amount of each salt on a metal spatula and heat directly on the flame and observe the colour imparted to the flame.

    3. Solubility test

We take three beakers containing water, petrol and kerosene and add small amount of each salts to these liquids.

    4. Electrical conductivity test

We set up an electric circuit using battery, bulb and electrodes and prepare aqueous solutions of each salt. Now we dip electrodes into each solution and observe whether the bulb glow or not.

Observation

Property	NaCl	KI	BaCl2
Physical state	Solid crystalline	Solid crystalline	Solid crystalline
Flame colour	Yellow	Violet	Green
Soluble in water	Yes	Yes	Yes
Soluble in petrol/kerosene	No	No	No
Electrical conductivity	Yes	Yes	Yes

 

Explanation

These all salts are ionic compounds and exits in solid state. Different metal ions impart distinct colour to the flame when heated. These salts are soluble in water but insoluble in organic solvents like petrol and kerosene.

Aqueous solution of these salts conducts electricity because they dissociate into free ions in water.

Conclusion

This activity explains that ionic compounds are crystalline solids, soluble in water and conduct electricity. These salts give specific colours to the flame when heated.

 

Frequently Asked Questions

   1. Why do ionic compounds conduct electricity in solution?

Answer – Because they produce free ions in water that carry electric current.

   2. Why do ionic compounds impart specific colours to flame?

Answer – Due to presence of metal ions in the ionic compounds.

    3. Are all salts ionic compounds?

Answer – Most of the salts are ionic compounds.