What is an acid?
A substance that produces hydrogen ions (H⁺) as the only positive ions when dissolved in water.
Give the ionization equation of hydrochloric acid.
HCl → H⁺ + Cl⁻
What is ionization?
The process by which a substance forms ions when dissolved in water.
What are organic acids?
Acids naturally found in plants and animals, e.g., citric acid and ethanoic acid.
What are inorganic acids?
Acids synthesized from minerals, e.g., HCl and H₂SO₄.
What is a strong acid?
An acid that completely ionizes in water.
Give two examples of strong acids.
Hydrochloric acid (HCl) and sulphuric acid (H₂SO₄).
What is a weak acid?
An acid that partially ionizes in water.
What is the basicity of an acid?
The number of replaceable hydrogen ions (H⁺) in one molecule of the acid.
What is the basicity of H₂SO₄?
2
State two physical properties of acids.
They turn blue litmus red and taste sour.
What happens when acids react with metals?
They produce a salt and hydrogen gas.
Write the equation for Zn reacting with HCl.
Zn + 2HCl → ZnCl₂ + H₂
What is neutralization?
The reaction between an acid and a base to form salt and water.
What is a base?
A substance that neutralizes an acid to form salt and water.
What is an alkali?
A base that dissolves in water.
State two characteristics of bases.
They turn red litmus blue and feel soapy.
Give one example of a strong alkali.
Sodium hydroxide (NaOH).
What is the pH scale?
A scale from 0 to 14 used to measure acidity or alkalinity.
What does pH = 7 indicate?
A neutral solution.
State the formula for calculating pH.
pH = -log₁₀[H⁺]
What is the relationship between pH and pOH?
pH + pOH = 14
What is a salt?
A compound formed when the replaceable hydrogen ions in an acid are substituted with metal or ammonium ions.
What is water of crystallization?
Water molecules chemically combined with a salt in its crystalline form.
What is efflorescence?
The loss of water of crystallization when a salt is exposed to air.
What is deliquescence?
The absorption of moisture from the air until a substance dissolves in it.
What is hygroscopicity?
The ability of a substance to absorb moisture from the air without dissolving.
What is a normal salt?
A salt formed when all replaceable hydrogen ions in an acid are replaced by metal ions.
What is an acid salt?
A salt formed when only part of the replaceable hydrogen ions are replaced.
What is hydrolysis of salts?
The process by which a salt reacts with water to form an acidic or basic solution.
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