Acids, Bases & Salts

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Acids, Bases & Salts

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TERMS

Topic 10: ACIDS, BASES & SALTS

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ACIDS are substances that form hydrogen ions (H+(aq)) when dissolved in water eg

Hydrochloric acid HCl gives H+(aq) and Cl-(aq) ions,

Sulphuric acid H2SO4 gives 2H+(aq) and SO42- ions

Nitric acid HNO3 gives H+(aq) and NO3-(aq) ions.

BASES are oxides and hydroxides of metals that react and neutralise acids to form salts and water only. Bases which are soluble in water are called alkalis. Not all bases fit into these categories e.g. ammonia.

Alkalis are substances that form hydroxide ions OH-(aq) in water eg

Sodium Hydroxide NaOH gives Na+(aq) and OH-(aq) ions,

Calcium Hydroxide Ca(OH)2 gives Ca2+(aq) and 2OH-(aq) ions.

جمعرات، 28 ربیع الثانی، 1438

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Topic 10: ACIDS, BASES & SALTS

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In acid solutions there are more H+ ions than OH- ions.

In alkaline solution there are more OH- ions than H+ ions.

Acids that dissociate (ionize) to a large extent are strong electrolytes and Strong Acids.

Acids that dissociate only to a small extent are Weak Acids and weak electrolytes

Bases can be strong or weak depending on the extent to which they dissociate and produce OH– ions in solution. Most metal hydroxides are strong electrolytes and Strong Bases. Ammonia, NH3, is a weak electrolyte and Weak Base.

جمعرات، 28 ربیع الثانی، 1438

Slide 4

Basicity of Acid

Topic 10: ACIDS, BASES & SALTS

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It is the number of ionizable H+ ions present in an acid e.g.

HCl is mono basic, it ionizes to produce one H+ ion

HCl ============== H+ + Cl-

H2SO4 is Dibasic, It ionizes to produce two H+ ions.

H2SO4 =============== 2H+ + SO42-

H3PO4 is Tribasic, it ionizes to produce three H+ ions.

H3PO4 ============== 3H+ + PO43-

جمعرات، 28 ربیع الثانی، 1438

Slide 5

Acidity of a Base

Topic 10: ACIDS, BASES & SALTS

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It is the ionizable OH- ions present in an alkali. e.g.

NaOH is monoacidic

NaOH ========== Na+ + OH-

Ca(OH)2 is diacidic

Ca(OH)2 ============== Ca2+ + 2OH-