Acids Bases and Salt Assignment 2022

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11 X – Science
CHAPTER – 2
ACIDS, BASES AND SALTS
q
Acids Bases
– Sour in taste – Bitter in taste
– Change the blue litmus to red – Change red litmus to blue
– eg. HydrochloricAcid HCl eg. Sodium hydroxide NaOH
– SulphuricAcid H2SO4 Potassium hydroxide KOH
– Nitric Acid HNO3 Calcium hydroxide Ca(OH)2
– Acetic Acid CH3 COOH – Ammonium hydroxide NH4OH
q Some Naturally occuring 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 Acid
q Acid – Base Indicators – Indicate the presence of an acid or base in a
solution.
q Litmus solution – It is a natural indicator. It is a purple day extracted from
Lichens. Other examples are Red Cabbage and coloured petals of Petunia
and turmeric.
q Olfactory indicators – Show odour changes in acidic or basic media. eg.
onion and clove.

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12 X – Science
q Acid – Base Indicators
S. No. Name of the Colour Change Colour Change
Indicator with Acid with Base
A. Blue litmus solution To red No change
B. Red litmus solution No change To blue
C. Turmeric No change To red
D. Methyl orange To red To yellow
E. Phenolphthalein (colourless) No change To pink
q Dilute Acid : Contains only a small amounts of acid and a large amount of
water.
q Concentrated Acid : A concentrated acid contains a large amount of acid and
a small amount of water.
q Chemical Properties of Acids and Bases
Acid + Metal → Salt + Hydrogen
(Refer activity 2.3 on page No. 19 of NCERT Book)
2HCl + Zn → ZnCl2 + H2
2HNO3 + Zn → Zn (NO3)2 + H2
H2SO4 + Zn → ZnSO4 + H2
2CH3COOH + Zn → (CH3COO)2 Zn + H2
q Pop test : When a buring 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.
q Base + Metal → Salt + Hydrogen
NaOH + Zn → Na2ZnO2 + H2
Sodium Zincate
Note – Such reactions are not possible with all the metals.

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13 X – Science
q Action of Acids with metal Carbonates and metal bicarbonates
Metal Carbonate + Acid → Salt + Carbondioxide + Water
Na2CO3(s) + 2HCl(aq) → 2NaCl(aq) + H2O(l) + CO2(g)
Metal bicarbonate + Acid → Salt + Carbondioxide + Water
NaHCO3 + HCl → NaCl + CO2 + H2O
q Lime water Test : On passing the CO2 gas evolved through lime water,
Ca(OH)2 (aq) + CO2(g) → CaCO3(s) + H2O(l)
Lime water White precipitate
On passing excess CO2 the following reaction takes place
CaCO3(s) + H2O(l) + CO2(g) → Ca(HCO3)2 aq
Soluble in water
q Neutralisation Reactions
Base + Acid → Salt + Water
NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
Neutralisation reacton takes place when the effect of a base is nullified by
an acid and vice versa to give salt and water.
q Reactions of metal oxides with acids
Metal Oxide + Acid → Salt + Water
CuO + HCl → CuCl2 + H2O
Copperoxide Hydrochloric Copper + Water
acid chloride
Note : Appearance of blue green colour of the solution because of formation
of CuCl2.
Metallic oxides are said to be basic oxides because they give salt and water
on reacting with acids.
q Reaction of Non Metallic Oxide with Base
Non metallic oxide + Base → Salt + Water
Ca(OH)2 + CO2 → CaCO3 + H2O