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SCIENCE 2PPISMP SEM. 2

SALTCATION & ANION

by

ANWAR HJ SULAIMAN

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LEARNING OUTCOME :

At the end of these topic the students will be able to :

1. prepare soluble and insoluble salt.

2. identifying cation and anion quantitively

3. explain and use the term solubility product (Ksp)

4. Calculate Ksp from given concentration and vice

versa

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SALT IN OUR DAILY LIFE.

1. Thousand of different type of salts exist naturally.2. Many type of salt in the sea such as .

3. Uses of salt :

(a) Agriculture

synthetic fertiliser / inorganic pesticide

(b) Medicinal field

plaster casts/ iron pills/laxatives/ anti-

acid/barium meal/ disinfectant

(c) Food industry

flavouring / MSG / baking powder / preservative(d) Chemical industry

bleching agent/ toothpaste / washing soda

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WHAT IS SOLUBLE & INSOLUBLE SALT?

1. A salt is an ionic compound containing cation (eg

metal ion) and anion (eg Cl2, NO3,SO4)2. Soluble salt are salt that can dissolve in water at

room temperature. Insoluble salt are salts that

cannot dissolve in water at room temperature.

3. Solubility of salt :

(a) All Na, K, NH4 salt soluble in water.

(b) All Cl salt soluble except AgCl, PbCl2, HgCl

(PbCl2 soluble in hot water)

(c) All SO4 salts are soluble except PbSO4, BaSO4

and CaSO4(d) All ethanoate salts are soluble in water

(e) All CO3 salt are INSOLUBLE except K2CO3,

Na2CO3 and (NH4)2CO3

4. The method use prepare a salt depends on the typeof the salt

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FORMATION OF SALT FROM DIFFERENT ACID

ACID TYPE OF SALT EXAMPLES OF SALTSHCl Chloride salt NaCl, ZnCl2, CuCl2, PbCl2, NH4Cl

H2SO4 Sulphate salt K2SO4, CaSO4, MgSO4, FeSO4, CuSO4

HNO3 Nitrate salt NaNO3, Mg(NO3)2, Al(NO3)3, Pb(NO3)2

H2SO3 Sulphate salt Na2SO3, CaSO3, MgSO3. ZnSO3

CH3COOH Ethanoate salt CH3COONa, CH3COOK

H2CO3 Carbonate salt K2CO3, CaCO3, ZnCO3, PbCO3

H3PO4 Phospate salt Na3PO4, Ca(PO4)2, Mg3(PO4)2

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PREPARATION OF SOLUBLE SALT.

Soluble salt of K+

/ Na+

/ NH4+

1. Acid + alkalis salt + water2. Add an acid to alkalis through titration method until

the alkalis exactly neutralised with the help of

indicator (pH=7)3. Repeat thye mixing without indicator

4. Heat the solution formed until it becomes saturated.

5. Allow it to crystalise by cooling

6. Filter and wash with small amount of distilled water7. Press the crystals between a few pieces of filter

paper to be dried.

Ref pg 203

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PREPARATION OF SOLUBLE SALT.

Soluble salt WHICH ARE NOT K+

/ Na+

/ NH4+

1. Acid + metal oxide salt + water2. Acid + metal carbonate salt + water + carbon

dioxide

3. Acid + metal salt + hydrogen4. Add excess solid metal/metal oxide/metal carbonate

into an acid with stirring.

5. Filter to remove excess solid.

6. Heat the filtrate until it becomes saturated.7. Allow it to crystalise by cooling

8. Filter and wash with small amount of distilled water

9. Press the crystals between a few pieces of filter

paper to be dried (Ref pg 206)

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PREPARATION OF INSOLUBLE SALT.

( eg lead iodide , lead chromate and barium sulphate.)

1. Insoluble salt can be prepare by precipitation

method through double decompisition reaction.

2. MIX two solutions which contain the require cations

and anions respectively to form a precipitate of the

insoluble salt3. Filter and wash the insoluble solid with distilled

water

4. Press the solid between a few pieces of filter paper

to be dried

(Ref pg 209)

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CONCLUSION

1. Salt have manu uses in our daily life such as inagriculture, medical, food and chemical industry

2. Salt divided into soluble and insoluble salt.

3. Determine the salt properties by doing :

(a) Prelimenary examination of physical properties

such as physical state, colour and solubility in

water

(b) Test for gases produced.

(c) Identify for anion and kation of the salt.

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END