Download Assistance Lecturer Amjad Ahmed Jumaa Arrhenius theory of acids

Inorganic chemistry
 Arrhenius theory of acids and
bases.
 Arrhenius acids.
 Arrhenius bases.
Assistance Lecturer Amjad Ahmed Jumaa
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 Acids and Bases:
Savante Arrhenius (1884) proposed his concept of acids and
bases.
 Arrhenius theory of acids and bases:
 Arrhenius acids:
An acid is a substance that when dissolved in water, releases
(H+), or (increase the concentration of hydronium ion, H3O+
(aq)).
For example: HCl is an Arrhenius acid.
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HCl (aq)
H+ (aq) + Cl-(aq).
 Arrhenius bases:
A base is a substance when dissolved in water, release (OH-),
ions, or (increase the concentration of hydroxide ion, OH(aq)).
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2O


NaOH(aq) H
OH- (aq) + Na+(aq).
Arrhenius acids:
Were generally recognized as a substance that in aqueous solution,
would:
1- Taste sour when diluted enough to be tasted.
2- Cause litmus paper to change from blue to red.
3- React with active metals such as magnesium, zinc, and iron to
produce hydrogen gas, H2 (g):
For example:
Hydrochloric acid HCl (aq),(Arrhenius acid), react with magnesium
metal to produce hydrogen gas and magnesium chloride:
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2HCl (aq) + Mg(s)
→ H2 (g) + MgCl2 (aq).
4- React with bases (they contain hydroxide ion, OH-), to
form water and compounds called salts.
For example: hydrochloric acid, HCl (aq), react with
potassium hydroxide, KOH (aq) as a base, to form water and
potassium chloride (salt).
HCl (aq) +KOH (aq) →
Acid
base
H2O + KCl(aq).
salt.
Salts: is formed (is made up) of the cation from the base and
the anion from the acid.
The reaction of an acid with a base called neutralization.
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 Neutralization:
If the correct amounts of acids and bases are mixed together,
the original properties of the acid and bases are lost. The
reaction product has a taste that is salty sour or bitter. A salt
and water were formed when an acid neutralizes a base.
For example:
H2SO4 (aq) + 2KOH (aq) →
Acid
base
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2H2O (l) +K2SO4 (aq).
salt.
 Arrhenius bases:
(also called alkalies), were generally recognized by
Arrhenius as that substance that in aqueous solution would:
1-Taste bitter (chemical used in the laboratory should never
be tasted.
2- Feel slippery or soapy on the skin
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3- Cause red litmus to change from red to blue.
4- React with acids to form water and salts.
NaOH (aq) + HBr(aq) → H2O(l) + NaBr(aq).
And thus: if you want to know wither a given compound, is
an Arrhenius acid or base, just dissolve some of it in pure
water and put a drop or two of the solution on blue litmus
paper:
If the litmus turns red, the compound is an acid, however if
the solution turns red litmus to blue, the presence of a base
compound is indicated.
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 Many foods are acidic, cider vinegar contains acetic acid,
lemons and other citrus fruits as well as many fruitflavored drinks contain citric acid.
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