Acids, Bases & Salts

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جمعرات، 28 ربیع الثانی، 1438

Slide 29

Topic 10: ACIDS, BASES & SALTS

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جمعرات، 28 ربیع الثانی، 1438

Slide 30

Making Insoluble Salts

Topic 10: ACIDS, BASES & SALTS

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This involves mixing solutions of two soluble salts that between them contain the ions that make up the insoluble salt. It is made by two methods.

PRECIPITATION

BaCl2(aq) + MgSO4(aq)  BaSO4(s) + MgCl2(aq)

DIRECT COMBINATION

Fe + S ---heat---- FeS

جمعرات، 28 ربیع الثانی، 1438

Slide 31

Topic 10: ACIDS, BASES & SALTS

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PRECIPITATION REACTION

جمعرات، 28 ربیع الثانی، 1438

Slide 32

Types of Salts

Topic 10: ACIDS, BASES & SALTS

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Normal Salts:

Normal salts are formed when all the replaceable hydrogen ions in the acid have been completely replaced by metallic ions.

HCl(aq) + NaOH(aq)  NaCl(aq) + H2O(l)

H2SO4(aq) + ZnO(aq)  ZnSO4(aq) + H2O(l)

Normal salts are neutral to litmus paper.

جمعرات، 28 ربیع الثانی، 1438

Slide 33

Topic 10: ACIDS, BASES & SALTS

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Acid salts:

Acid salts are formed when replaceable hydrogen ions in acids are only partially replaced by a metal. Acid salts are produced only by acids containing more then one replaceable hydrogen ion. Therefore an acid with two replaceable ions e.g. H2SO4 will form only one acid salt, while acid with three replaceable hydrogen ions e.g. H3PO4 will form two different acid salts.

H2SO4(aq) + KOH(aq)  KHSO4(aq) + H2O(l)

H3PO4(aq) + NaOH  NaH2PO4(aq) + H2O(l)

H3PO4(aq) + 2NaOH(aq)  Na2HPO4(aq) + 2H2O(l)

An acid salt will turn blue litmus red. In the presence of excess metallic ions an acid salt will be converted into a normal salt as its replaceable hydrogen ions become replaced.

KHSO4(aq) + KOH ================ K2SO4(aq) + H+O(l)

جمعرات، 28 ربیع الثانی، 1438