2. - Natural acid rain
- CO₂ in the air dissolves in the water in
clouds forming Carbonic acid (weak acid)
- When this weak acid falls on
limestone a reaction occurs and some
of the limestone is washed away.
Cracks called grikes appear
3. - In most of the places where most of the
limestone surface is dissolved away,
pinnacles of rock appear.
4. - The acid rain sinks into the rock and
forms underground streams.
- The water passing in the underground streams
dissolves more rock and forming caves.
5. - As the caves grow
bigger the walls become
weaker and collapse
forming a gorge.
6. - Fuels such as coals and oil contain sulphur.
- When the fuel is burnt it reacts with the oxygen
in the air to form sulphur dioxide.
- The sulphur dioxide reacts with the oxygen and
water in the air to form sulphuric acid.
- Factories and cars also produce nitrogen oxides
which produces nitric acid.
7. - When acid rain reaches
the ground it dissolves
some of the minerals in
the soil and carries
them away. This is
called leaching.
8. - Some of these minerals
are needed for healthy
growth of the plants
