SLIDE SHOW OF FULL CONTENT OF THE LESSON GIVEN CBSE SCIENCE TEX BOOK FOR STD. 10

2. Indicators:
 An indicator is a dye that changes colour with acids and bases
 Natural indicators
(litmus, turmeric)
 Synthetic indicators
(methyl orange, phenolphthalein)
 Olfactory indicators
( vanilla, onion, clove )

3. Sample Blue litmus Red litmus
Phenolptha
lein
Methyl
Orange
acid red no change colourless red
base no change
blue pink yellow

4. Acids and Bases in the laboratory
Acid
 It has sour taste
 It turns blue litmus to red
 Acid solutions conduct
current
 Strong Acids: HCL, H2SO4
 Weak Acids : CH3COOH
Base
 It has bitter taste
 It turns red litmus to blue
 Bases are electrolytes
 Strong Base: NaOH, KOH
 Weak Base: NH4OH

5. Action of Acids & Bases with Metals
Acid /Base + Metal Salt + Hydrogen gas
o Zn + H2SO4 ZnSO4 + H2
o Zn + 2NaOH Na2ZnO2 + H2
o chemical displacement

6. •Action of Metal Carbonates & Metal Hydrogen
carbonates with Acid
Carbonates + acid salt + carbon di oxide + water
Na2CO3 + 2HCl 2NaCl + H2O + CO2
NaHCO3 + 2HCl NaCl + H2O + CO2

7. Reaction of Metallic/Non metallic Oxides with Acids
# Metal Oxide + Acid Salt + Water
CuO + 2HCl CuCl2 + H2O
# Non metallic Oxide + base Salt + Water
Ca(OH)2 + CO2 CaCO3 + H2O
* products are similar to the products of neutralisation
• Metallic oxides are known as basic oxides
•Non-Metallic Oxides are called acidic oxides

9. What Happens to an Acid or a Base in a water solution?

10. Preparation of HCl

11. Acid and Bases in a water solution
 HCl + H2O H3O + Cl
 NaOH + H2O Na + OH
 HX + MOH MX + HOH (H2O)
 The process of dissolving an acid or base in water is a highly exothermic
 The process of mixing an acid and base with water is called dilution
- the dilution decreases the concentration of ions.

12. Strength of an acid and a base
 Universal Indicator is a mixer of several indicators
 It shows different colours at different concentrations H+ ions.
 pH Scale, used to measure the concentration of H+ ions.
 ‘p’ In pH stands for ‘potenz’ in German, meaning power.

14. Importance of pH in everyday life
 Our body works within the pH range of 7.0 to 7.8
 pH in our digestive system, antacids (Mg(OH)2)
 Tooth decay (corrosion of enamel) starts
when the pH of the mouth is <5.5…..to prevent
this tooth paste (basic)are used

15. What are present in acids and bases?
 hydrogen is common to all acids
 acids produce hydrogen ions(H+) in solutions
 these ions were responsible for their acidic properties
 hydroxyl ions (OH- ) are present in bases

16.  If the pH of rain water is <5.6, it is called acid rain
 Acid rain flows into the river and lowers the pH of the river
water
 Plants require a specific pH for their healthy growth
 Self defence by animals and plants ( honey bee injects HCOOH-
baking soda for relief from pain)

18. Neutralisation
Acid + Base Salt + Water

19. The process of dissolving an acid or a base
in water is a highly exothermic one.
The acid must always be added slowly to
water with constant stirring
A process of mixing an acid or base with
water is called dilute, it decreases the
concentration of ions.
C a r e o f a c i d s

20. F a m i l y o f S a l t s
pH = 7 Salts of strong acids and bases
pH > 7 Salts of strong base , weak acid
pH < 7 Salts of weak base , strong acid

21. • It is an important raw material for many substances
 NaOH ………. Causti soda
 Na2CO3 ……………. Washing Soda
 NaHCO3 ……………. Baking Soda
 CaOCl2 ………. Bleaching Powder
 CaSO4.1/2H2O … Plaster of Paris

22. • it is manufactured by the electrolysis of brine solution
• This process is known as Chlor –alkali process
• 2Nacl + 2H2O 2 NaOH + Cl2 + H2
• All three products are most useful
• H2(fuel-margarine ), Cl2 (cosmotics pesticides, water treatment)
NaOH ( de-greasing metals, soaps detergents and artificial paper)

23. it is manufactured by the action of CO2 with aq.NaCl
NaCl + H2O + CO2 + NH3 NH4Cl + NaHCO3
Uses : - for making baking powder( NaHCO3+tartaric acid)
- as an ingredient in antacids
- soda-acid fire extinguisher

24. it is obtained by heating baking soda
 2NaHCO3 Na2CO3 + H2O + CO2
Uses : - as cleansing agent
- for removing hardness of water
-in making of borax
- paper, glass, and soap industries

25. it is prepared by the action of Cl2 on dry s-lime
 Ca(OH)2 + Cl2 CaOCl2 + H2O
Uses : - for bleaching cotton ,wood pulp &
washed clothes
- as an oxidising agent
- for disinfecting drinking water

26. Are the crystals of salts really dry?
 CuSO4 . 5H2O - - - - blue vitriol
 FeSO4. 7H2O - - - - - green vitriol
 Na2CO3. 10H2O - - - - washing soda
 CaSO4. 2H2O - - - - gypsum

27. it is obtained on heating gypsum at 373K,
loses water molecule and becomes
Calcium sulphate hemi hydrate
 CaSO4. 2H2O CaSO4.1/2H2O + 1/2H2O
Uses : - for making toys, materials for
decoration and for making surfaces smooth