2. • In our everyday lives, we use many which
scientists call acids.
The orange or grapefruit juice you drink for breakfast
contains citric acid (also known as Vitamin C).
When milk turns sour, it contains lactic acid.
The vinegar used in salad dressing contains acetic
acid.
• According to this, a chemical bond is considered as
being made up of an acid-base combination. The
properties of a molecule, therefore, can be understood
by dividing it into acid and base fragments.
3. WHAT ARE ACIDS AND BASES?
Acids and Bases Definition
• An acid is any hydrogen-containing substance
that is capable of donating a proton (hydrogen
ion) to another substance.
• A base is a molecule or ion able to accept a
hydrogen ion from an acid.
4. WHAT ARE ACIDS AND BASES?
Acids and Bases Definition
• Acidic substances are usually identified by their
sour taste. An acid is basically a molecule which
can donate an H+ ion and can remain
energetically favourable after a loss of H+. Acids
are known to turn blue litmus red.
5. WHAT ARE ACIDS AND BASES?
Acids and Bases Definition
• Bases, on the other hand, are characterized
by a bitter taste and a slippery texture. A
base that can be dissolved in water is
referred to as an alkali. When these
substances chemically react with acids, they
yield salts. Bases are known to turn red
litmus blue.
6. LITMUS PAPER
• In order to find the numeric value of the level of acidity or basicity
of a substance, the pH scale (wherein pH stands for ‘potential of
hydrogen’) can be used. The pH scale is the most common and
trusted way to measure how acidic or basic a substance is. A pH
scale measure can vary from 0 to 14, where 0 is the most acidic
and 14 is the most basic a substance can be.
• Another way to check if a substance is acidic or basic is to use
litmus paper. There are two types of litmus paper available that can
be used to identify acids and bases – red litmus paper and blue
litmus paper. Blue litmus paper turns red under acidic conditions
and red litmus paper turns blue under basic or alkaline conditions.
7. LITMUS PAPER
• A litmus paper measures the pH levels of common household
substances to determine if they are acidic or basic.
• The pH is measured on a scale of 0-14.
• If the substance has a pH level of below 7, then it is acidic.
• If the substance’s pH level is above 7, then it is basic.
• Red litmus paper can turn either blue or red when immersed in a
substance.
• Red litmus paper turns blue if a substance is basic, while blue
litmus turns red if a substance is acidic.
• The color remains unchanged if the substance is neutral.
8. THEORIES OF ACIDS AND BASES
• Three different theories have been put forth
in order to define acids and bases. These
theories include the Arrhenius theory, the
Bronsted-Lowry theory, and the Lewis
theory of acids and bases.
9. THEORIES OF ACIDS AND BASES
Acids and bases can be defined via three different
theories.
• The Arrhenius theory of acids and bases states that “an
acid generates H+ (Hydrogen) in a solution
whereas a base produces an OH- (Hydroxide) ion in its
solution”.
• The Bronsted-Lowry theory defines “an acid as a proton
donor and a base as a proton acceptor”.
• Finally, the Lewis definition of acids and bases
describes “acids as electron-pair acceptors and bases
as electron-pair donors”.
10. ACIDS
• There are many different kinds of acids…
• The strong acids are acids that are completely
when dissolved in water by losing one proton.
- a common example of strong acid is hydrochloric
acid, the acid that the stomach uses to break down proteins.
• Strong acids have very low pH (0-4).
• But there are also acids that are not as corrosive.
- one example is the ascorbic acid or more commonly
known as Vitamin C, which helps the human body’s
immune system. Citrus fruits are also classified as acidic.
11. CHARACTERISTICS OF ACIDS
• Below are some common characteristics of acids:
acids taste sour in .
Acids change blue litmus paper to red.
Acids reacts with metals to produce hydrogen gas.
Acids contain hydrogen. When dissolved in water, acids
ionize to produce positive hydrogen ion (H+)
Acids are proton donors.
Acids have a 1 to 6 pH value.
Acids, when mixed in water, conduct electric current.
Acids are classified into binary acid (HCl, HBr, HF, H2S) and
oxyacid (H2CO3, HClO3, HNO3, CH3COOH)
12. COMMON ACIDS
NAME FORMULA USES
Nitric Acid HNO3 Explosives
Phosphoric
Acid
H3PO4 Fertilizers
Carbonic
Acid
H2CO3
Carbonated drinks,
stalactites and
stalagmites
Ascorbic
Acid
C6H8O6 Vitamin C
Acetic Acid HC2H3O2 Vinegar
13. BASES
• Bases, also called alkalines, are substances that consume
or neutralize acids.
• When acids come in contact with bases, they lose their
characteristic sour taste and ability to dissolve metals.
• Just like acids, there are also strong bases.
• Any base that has very high pH level (10-14) is classified
as a strong base.
14. CHARACTERISTICS OF ACIDS
• Below are some common characteristics of bases:
Bases taste bitter in aqueous solution.
Bases change red litmus paper to blue.
Bases feel slippery to the touch.
Bases ionize in water to form Hydroxides (OH-).
Bases, when mixed in water, conduct electric current.
Bases are proton acceptors.
Bases have an 8 to 14 pH value.
15. COMMON BASES
NAME FORMULA USES
Aluminum
hydroxide
Al(OH)3 Deodorant
Iron (III)
hydroxide
Fe(OH)3 Cosmetics
Sodium
hydroxide
NaOH For soap making
Barium
hydroxide
Ba(OH)2 For titration
Magnesium
hydroxide
Mg(OH)2 Antacid
16. NEUTRAL/NEUTRAL SOLUTION
• A solution that is neither acidic or basic
is said to be neutral.
• A neutral solution has a pH of 7.
Distilled water is one example of a
neutral solution
17.
18. COMPOUND
A compound is a pure substance similar to
an element. However, it represents a combination
of two or more elements that are chemically
combined in a fixed mass ratio to form a new
substance known as a molecule.
MOLECULE a group of atoms bonded
together, representing the smallest fundamental
unit of a chemical compound that can take part in a
chemical reaction.
20. IONS
An ion is defined as an atom or
molecule that has gained or lost one or more
of its valence electrons, giving it a net
positive or negative electrical charge. In other
words, there is an imbalance in the number
of protons (positively charged particles) and
electrons (negatively charged particles) in a
chemical species.
21. IONIZATION
, or Ionisation is the
process by which an atom or a
molecule acquires a negative or
positive charge by gaining or losing
electrons
The resulting electrically charged
atom or molecule is called an ion.
