this power point includes and covers basic concepts of acids bases and indicators according to IGCSE chemistry curriculum

1. Year 11 chemistry
By: Mrs. Saima

2.  describe the use of the indicators litmus, phenolphthalein
and methyl orange to distinguish between acidic and
alkaline solutions
 understand how the pH scale, from 0–14, can be used to
classify solutions as strongly acidic, weakly acidic, neutral,
weakly alkaline or strongly alkaline
 describe the use of universal indicator to measure the
approximate pH value of a solution
 Definee acids and bases in terms of proton transfer
 Describe the meaning of weak acids and bases
 Describe neutrality and relative acidity and alkalinity in terms of
pH measured using universal indicator paper (whole numbers
only)
 Describe and explain the importance of controlling acidity in soil

3.  SOME COMMON ACIDS
 Acids and alkalis are not only found in chemistry labs,
they are actually very common. We use acids and
alkalis in our daily lives for things like cleaning,
cooking and you even eat and drink some substances
that are acidic or alkaline.
 Common lab acids include:
 Hydrochloric acid
 Sulfuric acid
 Nitric acid
 Acids can be found in everyday products like:
 Fizzy drinks
 Vinegar
 Fruit juices

4.  Common lab alkalis include:
 Sodium hydroxide
 Potassium hydroxide
 Ammonia
 Alkalis are found in everyday products like:
 Oven cleaner
 Baking soda
 Drain unblocker

5.  Acids have pH values of below 7, have a sour
taste and are corrosive
 In acidic conditions blue litmus paper turns
red and methyl orange indicator turns red
 Acids are substances that can neutralise a
base, forming a salt and water
 When acids react, they will form positively
charged hydrogen ions (H+)
 The presence of H+ ions is what makes a
solution acidic

7.  Equations for neutralisation
ACID + BASE  SALT + WATER
HCl +NaOH  NaCl + H₂O
Neutralisation is the reaction of an acid with a base that
results in the pH moving towards seven. It is a useful process
that occurs in everyday life such as in the treatment of acid
indigestion and the treating of acidic soil by adding lime.
When an acid is neutralised, its pH increases towards seven.
When an alkali is neutralised, its pH decreases towards
seven.
Several different bases can neutralise acids, and water is
always produced as a result of these reactions.

8.  Neutralization of soil is sometimes necessary in order to
promote plant growth. The ability of plants to take
nutrients from the soil into their roots is affected by the pH
content of the surrounding soil particles. Acid rain can
cause soil to become acidic. Some plants benefit from
liming the soil. In the liming process, agricultural limestone-
calcium carbonate (CaCO3) that may also contain
magnesium carbonate (MgCO3) neutralizes acid in the soil
and provides nutrients to promote plant growth. Since
liming can stimulate plant growth, it is important to also
fertilize limed soil.