CBSE Class 10 Science
Revision Notes
CHAPTER 2
ACIDS, BASES AND SALTS
Acids Bases
Sour in taste
Bitter in taste
Derived from Greek word' ACIDUS'
Changes blue litmus into red Changes red litmus into blue
e.g. Hydrochloric acid HC1 e.g. Sodium hydroxide NaOH
Sulphuric acid H2 SO4 Potassium hydroxide KOH
Nitric acid HNO3 Calcium hydroxideCa(OH)2
Acetic acid CH3 COOH Ammonium hydroxide
" Some naturally occurring acids
Vinegar Acetic Acid
Orange Citric Acid
Lemon Citric Acid
Tamarind Tartaric Acid
Tomato Oxalic Acid
Sour milk (Curd) Lactic Acid
Ant and Nettle sting| Methanoic Ac
" Acid- Base Indicator:Substances which indicate the presence of an acid or base in a
solution.
" Litmus solution It is a natural indicator. It is a purple dye extracted from Lichens.
Other examples are Red Cabbage and coloured petals of Petunia and turmeric.
Olfactory indicators :Show odour changes in acidicor basic media. E.g. onion and
, clove
Acid - Base Indicators
S.No. Name of the Indicator Colour Change With Acid| Colour Change with Base
A. Blue litmus solution To red No change
B. Red litmus solution No change To blue
C. Turmeric No change Tored
D. Methyl orange To red To yellow
E. Phenolphthalein (colourless) Nochange To pink
Dilute Acid: A dlute acid contains a small amount of acid (lower concentration of
hydronium ions)and a large amount of water.
" Concentrated Acid :A concentrated acid contains a large amount of acid (higher
concentration of hydronium ions)and a small amount of water.
" Chemical Properties of Acids and Bases
1. Reaction with metal
Acid + Metal ’ Salt + Hydrogen
2HCl +Zn’ ZnCly + H,
2HNO; + Zn’Zn(NO3)2 + H)
H, S04 + Zn’ ZnSO4 + H)
2CH,COOH +Zn’
(CH_CO0)2Zn + H,
Pop test:When a burning candle is brought near a test tube containing hydrogen gas
it burns with a Pop' sound. This test is conducted for examining the presence of
hydrogen gas.
" Base + Metal ’ Salt + Hydrogen
NaOH + Zn ’ NagZnO, + H,
Sodium Zincate
Revision Notes
CHAPTER 2
ACIDS, BASES AND SALTS
Acids Bases
Sour in taste
Bitter in taste
Derived from Greek word' ACIDUS'
Changes blue litmus into red Changes red litmus into blue
e.g. Hydrochloric acid HC1 e.g. Sodium hydroxide NaOH
Sulphuric acid H2 SO4 Potassium hydroxide KOH
Nitric acid HNO3 Calcium hydroxideCa(OH)2
Acetic acid CH3 COOH Ammonium hydroxide
" Some naturally occurring acids
Vinegar Acetic Acid
Orange Citric Acid
Lemon Citric Acid
Tamarind Tartaric Acid
Tomato Oxalic Acid
Sour milk (Curd) Lactic Acid
Ant and Nettle sting| Methanoic Ac
" Acid- Base Indicator:Substances which indicate the presence of an acid or base in a
solution.
" Litmus solution It is a natural indicator. It is a purple dye extracted from Lichens.
Other examples are Red Cabbage and coloured petals of Petunia and turmeric.
Olfactory indicators :Show odour changes in acidicor basic media. E.g. onion and
, clove
Acid - Base Indicators
S.No. Name of the Indicator Colour Change With Acid| Colour Change with Base
A. Blue litmus solution To red No change
B. Red litmus solution No change To blue
C. Turmeric No change Tored
D. Methyl orange To red To yellow
E. Phenolphthalein (colourless) Nochange To pink
Dilute Acid: A dlute acid contains a small amount of acid (lower concentration of
hydronium ions)and a large amount of water.
" Concentrated Acid :A concentrated acid contains a large amount of acid (higher
concentration of hydronium ions)and a small amount of water.
" Chemical Properties of Acids and Bases
1. Reaction with metal
Acid + Metal ’ Salt + Hydrogen
2HCl +Zn’ ZnCly + H,
2HNO; + Zn’Zn(NO3)2 + H)
H, S04 + Zn’ ZnSO4 + H)
2CH,COOH +Zn’
(CH_CO0)2Zn + H,
Pop test:When a burning candle is brought near a test tube containing hydrogen gas
it burns with a Pop' sound. This test is conducted for examining the presence of
hydrogen gas.
" Base + Metal ’ Salt + Hydrogen
NaOH + Zn ’ NagZnO, + H,
Sodium Zincate
