Acids Bases and Salts
STD-7 (2014)
1. Name two mineral acids.
Sulphuric Acid and Nitric Acid.
2. How does an acid taste?
Acids are sour in taste.
3. Name the acid present in sour milk.
Lactic Acid is present in sour milk.
4. Write the chemical formulae for hydrochloric acid and sulphuric acid.
HCl – Hydrochloric acid, H2SO4 - Sulphuric Acid.
5. Name the gas produced when acids react with metals.
Hydrogen is the gas produced when acids react with metals.
6. What is milk of magnesia?
Milk of magnesia is an antacid consumed, when one suffers from acidity. It
neutralises the effect of the hydrochloric acid secreted in the stomach due to the
presence of a constituent base called magnesium hydroxide or milk of magnesia.
7. What are the products of a neutralisation reaction.
Salt and water are the products of the neutralisation reaction.
8.1 Differentiate between Acids and Bases
Acids
Bases
Taste
Sour
Bitter
Feel
Concentrated acids can cause
skin burn; care should be taken
while handling acids
Bases often feel slippery or soapy;
Concentrated bases can cause skin
burn ;care should be taken while
handling bases
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Reaction Turn blue litmus paper RED
to Litmus
Paper
Reactions React the bases to form salt and
water (neutralisation reaction)
Examples
Turn red litmus paper BLUE
React the acids to form salt and water
(neutralisation reaction)
Sulphuric acid used in
car batteries
Stomach acid
(hydrochloric acid)
Household Vinegar
(acetic acid)
Lemon juice, orange
juice, or citrus fruit
juices(citric acid)
Drain cleaner, oven cleaner
(sodium hydroxide)
Cleaning products (ammonium
solution)
Milk of Magnesia (magnesium
hydroxide) used as antacid
8.2 Differentiate between Mineral acids and Organic acids
Mineral Acids
Organic Acids
Derived from minerals
Derived from fruits and
vegetables
Eg: Lactic acid, citric acid
Eg: Sulphuric acid, Nitric acid
8.3 Differentiate between Bases and Alkalis
Bases
Alkalis
They are substances which
produce hydrogen ions (OH)when added to water
Eg: Zinc oxide, Magnesium oxide
Bases which are soluble in water are
called alkalis
Eg: Sodium Hydroxide
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9 Define acids and bases citing two examples for each of them.
Acids: They are substances which produce hydrogen ions (H+) when dissolved in
water. Eg: sulphuric acid and nitric acid
Bases:They are substances which when added to water produces hydroxide ions
(OH-). Eg: calcium hydroxide and sodium hydroxide
10 Mention any four properties of acids.
The properties of acids are as follows:
Acids are corrosive in nature and sour in taste
Acids change Blue litmus to RED in colour.
Acids react with metals to form hydrogen gas and salt
Acids react with bases to form salt and water.
11. What are indicators? Give two examples along with their colour changes in acidic and
basic media.
An indicator is a compound that changes colour when added to acidic or basic
substances.
Examples:
Acids
Bases
Litmus
Turns blue litmus RED
Turns red litmus BLUE
Phenolphthalein
No change in colour
Turns PINK
12.Is baking powder acidic, basic or neutral? How would you justify your answer?
Sodium Bicarbonate or baking powder is NaHCO3 . It is a salt which means it is
neutral and it produces H+ ions when dissolved in water .
13.. What is a neutralisation reaction? Give an example.
Reaction between an acid and a base to form salt and water is known as neutralization
reaction.
Hydrochloric acid + Sodium Hydroxide  Sodium Chloride + Water
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14. What should be done to get relief from a bee sting and why ?
To get relief from a bee sting, vinegar (acetic acid) should be immediately applied.
This is because the bee sting is basic in nature, so to neutralise the effect of the base
we apply vinegar which is acidic in nature to nullify the effect of the base.
15. How does slaked lime help in the treatment of acidic soil?
Acidic soil is treated with bases like slaked lime, which is actually calcium hydroxide
or chalk powder, to nullify the effect of the acid. This process leads to the
neutralisation of the soil which promotes the growth of crops/plants.
16. USES OF ACIDS:
Sulphuric acid
used in car and inverter batteries
used in manufacture of fertilizers
Nitric acid
used to make explosives like trinitrotoluene (TNT) and
nitroglycerine
used to manufacture artificial silk, synthetic dyes and fertilizers.
Hydrochloric
acid
Used in preparation of cleaning liquids.
It’s the main stomach acid and helps in digestion.
Used for manufacturing of chlorine.
Used for the preparation of aqua regia.
Acetic acid
Used as a preservative.
Carbonic acid
Used in preparation of aerated drinks.
17. USES OF BASES
Calcium
hydroxide
(slaked lime)
Important constituent in many pesticides.
Used for neutralising acidic soil.
Acidic waste water is treated with calcium hydroxide before it is
disposed in water bodies.
Sodium
hydroxide
(caustic soda)
Potassium
Used to manufacture paper, textiles, soaps and detergents
Useful in preparation of biodiesel.
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hydroxide
(caustic
potash)
Magnesium
hydroxide
(Milk of
magnesia)
Ammonium
hydroxide
Is a wonderful antacid.
used in manufacture of household cleaners.
18. USES OF SALTS
Sodium
chloride
(common salt)
Used in food to enhance taste.
Used for preserving pickles.
Used for producing freezing mixture by adding to ice.
Used in manufacture of pulp and paper.
Used in setting dyes in textiles and fabrics.
Used for making soaps, detergents and other cleaning agents.
Sodium
carbonate
(washing
soda)
Sodium
bicarbonate
(baking soda)
Used to manufacture glass.
Used to softening hard water.
Copper
sulphate
Used in preparation of fungicides.
used as a wood preservative.
Used in baking cakes and breads.
Used in some aerated drinks.
Used in preparation of some medicines.
Used in preparation of fire extinguishers.
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