Acids and bases

Acids and BasesBy: Faiq & Rizan

AcidsProduce H+ ions in water

Have a sour taste

Break down metals

Formula starts with H

Poisonous and corrosive to skin

pH less than 7

Acidturn blue litmus red

Dissolve in water to form solution which conduct electricity

React with reactive metal metals to form salt and hydrogen (explained)

Acids react with carbonates and hydrogen carbonates to form a salt, water and carbon dioxide (explained)

Acids react with metal oxides and hydroxides to form a salt and water only(explained)

AlkalisProduce OH- ions in water

Have a bitter taste and a slippery feel

Break down fats and oils

Formula ends with OH

Poisonous and corrosive to skin

pH greater than 7

Alkalisturn red litmus blue

React with acids to form salt and water only.(explained)

Heated with ammonium salts gives off ammonia gas.(explained)

React with a solution of one metal salt to give another metal salt and metal hydroxide.(explained)

pH scale

Acid have pH of <7

Alkalis have pH of >7

Theories of acids and bases

Arrhenius Concept of Acids and Bases

According to the Arrhenius concept of acids and bases, an acid is a substance that, when dissolved in water, increases the concentration of hydronium ion (H3O+).

Remember, however, that the aqueous hydrogen ion is actually chemically bonded to water, that is, H3O+.

Arrhenius Concept of Acids and Bases

A base, in the Arrhenius concept, is a substance that, when dissolved in water, increases the concentration of hydroxide ion, OH-(aq).

Bronsted-Lowry Acid and Bases

Bronsted-Lowry Acid can donate a proton

Bronsted-Lowry Base can accept a proton

Must contain a non-bonding pair of electrons

Conjugate base of an acid is the species remaining after the acid has lost a proton


Conjugate acid is the species formed after the base has accepted a proton

HCl + H2O ↔ H3O+ + Cl-

Water is conjugate base of H3O+ and Cl- is conjugate base of HCl


Water can act both as acid and base. Amphiprotic

Strong acids have weak conjugate base

Weak acids have strong conjugate base

ACID: Ethanol (C2H5OH) =>weak

CONJUGATE BASE: Ethoxide ion (C2H5O-) => strong

Lewis Acids and Bases

Bases can donate a pair of electrons

Acids can accept a pair of electrons

Covalent bond is formed

Many Lewis Acids don’t contain hydrogen

Properties of Acids and Bases


Neutralization reaction with bases

With hydroxides to form salt and water

CH3COOH + NaOH NaCH3COO + H2O

With metal oxides to form a salt and water

H2SO4 + CuO CuSO4 + H2O

With ammonia to form salt

HCl + NH3 NH4Cl


With reactive metals to form salt and hydrogen

2HCl + Mg MgCl2 + H2

With carbonates to form salt, CO2, water

2HCl + CaCO3 CaCl2 + CO2 + H2O

With hydrogen carbonates to form salt, CO2, water

HCl + NaHCO3 NaCl + CO2 + H2O

Strong Acids and Bases

Strong acid and base is completely dissociated (ionized) into its ions in aqueous solutions

Strong acids

HCl (Hydrochloric acid)

HNO3 (Nitric Acid)

H2SO4 (Sulfuric Acid)

Strong Acids and Bases

Strong bases

NaOH (Sodium Hydroxide)

KOH (Potassium Hydroxide)

Ba(OH)2 (Barium Hydroxide)

Weak Acids and Bases

Weak acids and bases is slightly dissociated into their ions in aqueous solution

Weak acids

CH3COOH (Ethanoic Acid)

H2CO3(Carbonic acid)

Weak Acids and Bases

Weak bases

NH3 (Ammonia)

C2H5NH2 (Amino ethane)

Acidic oxides

Acidic oxides are the oxides of non-metals. When combined with water, they produce acids, e.g.,

Acidic oxides are, therefore, known as acid anhydrides, e.g., Sulphur dioxide is sulphurous anhydride; Sulphur trioxide is sulphuric anhydride.

Basic oxides

Basic oxides are the oxides of metals. If soluble in water they react with water to produce hydroxides (alkalis).

Basic oxides do not reacts with alkalis.

Examples:

CaO + H2O Ca(OH)2

MgO + H2O Mg(OH)2

Amphoteric oxides

Amphoteric oxides are metallic oxides, which show both basic as well as acidic properties. When they react with an acid, they produce salt and water, showing basic properties. While reacting with alkalis they form salt and water showing acidic properties

Neutral oxides

These are the oxides, which show neither basic nor acidic properties, that is, they do not form salts when reacted with acids or bases, e.g., carbon monoxide (CO); nitrous oxide (N2O); nitric oxide (NO), etc., are neutral oxides.

Thank You for reading and hope u all understand

Acids and bases

Education

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