Transcript ACID,BASE AND SALT

ACID,BASE AND SALT
By
IIN INDRIYATI
Biology Teacher of SMP 1 Wonosari
A. Competence Standard
B. Basic Competence
: 5. To understand the characteristic
of acid, base and salt
: 5.1 To identify the characteristic of
acid, base and salt by using
accurate tools and indicators
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Objective :
1. Student able to identify the characteristic of acid, base and
salt after do experiment
ACID
 Acid is a substance that releases hydrogen
ion ( H+) when it’s dissolved in water and a
negative ion will be formed according to the
following reaction :
 Acid
H+ + negative ion
example :
HCl
H+ + Cl –
(Hydrochloric acid)
H2SO4
2H+ + SO42(Sulfuric acid)
Acid characteristics
 There are corosive, meaning they can
destroy other materials including metal,
marble,
 They have sour taste
 They can conduct electricity.
 They can change blue litmus to red
 They have a pH of less than 7
Acids Affect Indicators, by
changing their color
Blue litmus paper turns red in
contact with an acid (and red paper stays
red).
Matters that contain acid

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Lemon
Tomato
Vinegar
Manggo
Starfruit
etc
Strong Acids
 Strong acids are very corrosive. They
react with metals and can cause severe
burns on the skin. They conduct
electricity well.
 Strong acids:
Hydrochloric HCl
Nitric
HNO3
Sulfuric
H2SO4
Hydrobromic HBr
Acids
have a
pH
less
than 7
Base
Base is substance that releases hydroxide
ion (OH-) when it’s dissolved in water and
positive ions are formed according to the
following reaction
Base
positive ion + OHExample : NaOH
Na+ + OHSodium hydroxide
NH4OH
NH4+ + OHAmmonium hydroxide
Base characteristics
 They
caustic, meaning they can damage
our skin or other materials
 They feel smooth on our hand
 They have bitter taste
 They can change red litmus to blue
Bases Affect Indicators
Red litmus paper
turns blue in contact
with a base (and blue paper Phenolphthalein
turns purple in a
stays blue).
base.
Bases
have a
pH
greater
than 7
Bases Neutralize Acids
Milk of Magnesia contains
magnesium hydroxide,
Mg(OH)2, which neutralizes
stomach acid, HCl.
2 HCl + Mg(OH)2
MgCl2 + 2 H2O
Magnesium salts can cause
diarrhea (thus they are used
as a laxative) and may also
cause kidney stones.
Matters that contain base
 Soap
 Detergent
 Thootpaste
 Baking
soda
 Stomach medicine/ Antasid (obat perut)
 etc
Common Bases
 Sodium
hydroxide NaOH
 Calcium hydroxide Ca(OH)2
 Magnesium hydroxide Mg(OH)2
 Ammonium hydroxide NH4OH
SALT
Salt is formed by reaction between acid
and base
 The reaction between Acid and Base is
called the neutralization reaction
 Acid + Base
Salt + Water
 Example : NaCl
 HCl (asam) + NaOH (basa) --------- NaCl
(garam dapur) + H2O (air)

Measuring pH
Why measure pH?
 Everyday solutions
we use - everything
from swimming pools,
soil conditions for
plants, medical
diagnosis, soaps and
shampoos, etc.
 Sometimes we can use
indicators, other times
we might need a pH
meter

How to measure pH with wide-range paper
1. Moisten the pH
indicator paper strip
with a few drops of
solution, by using a
stirring rod.
2.Compare the color
to the chart on the vial
– then read the pH
value.
Some of the
many pH
Indicators
and their
pH range
Acid – Base Indicators
Artificial indicators :
- Lithmus paper
- Universal indicator
- Phenolphthalein
- Red methil
- Blue bromthymol
 Natural indicators :
- Hibiscus
- Turmeric
- Red cabbage
- Mangosteen
SIFAT – SIFAT SENYAWA ASAM DAN BASA
Asam
Basa
1, Rasa asam
1, Rasa pahit / getir
2, Korosif
2, Kaustik
3, Memerahkan lakmus biru
3, Membirukan lakmus merah
4, pH < 7
4, pH > 7
5, Tidak berwarna dengan indikator pp
5, Berwarna merah dengan indikator pp
6, Dapat menetralkan senyawa basa
6, Dapat menetralkan senyawa asam
Thank’s you
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
See you next time
Good by