Acid and alkali

To study on Acid and Alkali

2. Acids have a sour taste.
They are corrosive.
An Acid is a sour tasting
liquid and highly corrosive
and turns into litmus red.

3. Acids
There are many acids
present in our everyday
lives.
Lemon juice contains citric acid, and vinegar
contains ethanoic acid.
Some strong acids are hydrochloric acid,
sulphuric acid and nitric acid.
Some weak acids are cid, citric acid and
carbonic acid.

4. Why are acid Why are acid
dangerous ?dangerous ?
Certain chemical properties make an acid dangerous. Certain chemical properties make an acid dangerous.
For e.g., sulphuric acid has the property of absorbing For e.g., sulphuric acid has the property of absorbing
water. Thus when it spills on the body, it can cause water. Thus when it spills on the body, it can cause
severe burns. Nitric acid similarly is an oxidizing agent. severe burns. Nitric acid similarly is an oxidizing agent.
It reacts violently with the skin, muscles and bones to It reacts violently with the skin, muscles and bones to
cause lethal damage. cause lethal damage.

5. Alkalis
An alkaline solution is a mixture
of base solids dissolved in water.
Alkalis react with acids and
neutralise them.
Everyday we use alkalis unknowingly.
They are slippery.
They are corrosive.

6. Why are alkalis
dangerous ?
Alkalis are dangerous . They should be 
given proper care. Even they have 
chances to burn our skin. And even the 
diluted sodium hydroxide solution can 
burn our skin.

7. Neutralisation
When acid and alkali react , a
process
called neutralization occurs in which
a salt and water is formed.

8. Indicators
They change colour in acid or alkaline solutions.

Different indicators change to different colours.
Indicators help
you find out
whether a
solution is
acidic or not.

9. Litmus
Test

Litmus is an indicator. It changes colour in acid
and alkaline solutions.

Litmus is red in an acid.

Litmus is blue in an alkali.

10. Universal Indicator

Universal indicator changes colour in acids
and alkalis.
Its colour shows the strength of an acid or alkali.

11. The pH scale
7

12. Applications of Neutralisation
•Curing Indigestion: When a tablet of sodium
bicarbonate is swallowed the chemical dissolves
to make an alkaline solution,which neutralises the
acid in the stomach and cures the indigestion.
• Insect Stings
Bee stings is acidic and may be
neutralized by soap,which is an alkali . A
wasp sting is alkaline an may be
neutralized with vinegar , which is a
weak acid.

13. Rainfall made sufficiently 
acidic by atmospheric 
pollution that it causes 
environmental harm, typically 
to forests and lakes.

14. \
When acid rain
reaches the ground,it
drain into the
soil,disssolves some
of the minerals there
and carries them
away.This process is
called leaching.

16. It help the plant the not get proper food and growth.It help the plant the not get proper food and growth.
It drains into rivers and lakes and lower the pH of
the water.
Many forms of water life are sensitive to pH of
water and cannot survive if it is too acidic.
If they are concentrated the can also damage
our skin.
They also damage the famous building like
tajmahal.