Common properties of acids and bases, ionisation, electrolyte, non-electrolyte,

1. Acids, Bases and Salts
Common Properties of Acids and Bases

2. CBSE - 10 Acids, Bases and Salts
Chemistry Common Properties of Acids and Bases
Acids and bases have two
common properties.
Common properties of acids and bases They conduct electricity and
undergo ionisation.
• They conduct electricity
• They undergo ioinisation These features can be explained
by conducting two experiments.
They are electrolytic conductance
and experiment with dry HCl gas
Experiments:
1. Electrolytic conductance
2. Experiment with dry HCl gas

3. CBSE - 10 Acids, Bases and Salts
Chemistry Common Properties of Acids and Bases
Electrolytic Conductance:
Bulb glows Bulb glows
1) Experiment with HCl Solution:
Switch 6v Battery 6 v Battery
Switch • Place a beaker filled with
hydrochloric acid solution.
• Dip two metal electrodes and
connect their terminals to a 6 volts
battery through a switch and a bulb.
Anode Cathode
Anode Cathode • Switch on the circuit.
• The bulb glows indicating the acid
solution conducts current.
2) Experiment with NaOH
Solution:
• Conduct the same experiment with
sodium hydroxide solution replacing
HCl Solution hydrocholric acid solution.
NaOH Solution
• The bulb glows in sodium
hydroxide solution.
1 2

4. CBSE - 10 Acids, Bases and Salts
Chemistry Common Properties of Acids and Bases
Electrolytic Conductance:
Bulb glows Bulb glows
3) Experiment with Sugar
Switch 6v Battery 6 v Battery Solution:
Switch
• Place another beaker filled with
sugar solution.
• Dip two metal electrodes and
connect their terminals to a 6 volts
Anode Cathode battery through a switch and a bulb.
Anode Cathode
• Switch on the circuit.
• The bulb does not glow indicating
the glucose solution does not
conduct electricity.
4) Experiment with NaOH
Solution:
Sugar Solution • Conduct the same experiment with
Alcohol Solution alcohol solution replacing sugar
solution.
3 4 • The bulb does not glow in alcohol
solution also.

5. Acids, Bases and Salts
Experiment Experimental Bulb Inference Inference:
Number Solutions
• Bulb glows in HCl and NaOH
1 HCl solution Glows Conducts current by
solutions because they conduct
ionisation
current by ionisation.
HCl  H+ + Cl-
• Bulb does not glow in sugar
2 NaOH solution Glows Conducts current by
and alcohol solutions because
ionisation
they do not undergo ionisation.
NaOH  Na+ + OH-
• Ionisation is a common
phenomenon in acids and
3 Sugar solution Does not Does not conduct
bases.
glow current, because
ionisation does not
occur
4 Alcohol solution Does not Does not conduct
glow current, because
ionisation does not
occur

6. CBSE - 10 Acids, Bases and Salts
Chemistry Aqueous Solutions
Experiment with Dry HCl gas:
• Take sodium chloride in a dry
test tube.
• Add concentrated sulphuric acid
Dry HCl gradually.
• Close the test tube with a
rubber cork fitted with a guard
tube containing calcium chloride.
• Hydrogen chloride is evolved
when sodium chloride reacts with
sulphuric acid in the test tube.
•The anhydrous calcium chloride
kept in the guard tube absorbs
traces of water.
• Hence dry HCl gas is obtained.
1 2

7. CBSE - 10 Acids, Bases and Salts
Chemistry Aqueous Solutions
Case-1:
Normal Blue Litmus
• Introduce a normal blue litmus
Paper
paper at the end of the delivery
Dry HCl Dry HCl tube where dry HCl gas is
evolved.
•The dry HCl gas does not
change the colour of the blue
litmus paper.
Case-2:
• Bring a moist blue litmus paper
at the delivery end of the HCl
gas.
•Dry HCl gase changes the
colour of moist blue litmus paper
to red.
3 4

8. CBSE - 10 Acids, Bases and Salts
Chemistry Aqueous Solutions
Inference:
Dry HCl gas No ionisation • Dry HCl becomes wet in moist
blue litmus paper
• The wet HCl ionises into
hydrogen cation and chloride
Normal Blue litmus paper anion.
• The release of H+ is significant
in the acidic nature of a
substance.
•It causes the moist litmus paper
turning red.
Ionisation
Wet HCl
H+ + Cl-
H2O
Moist Blue litmus paper turns red