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Neutralization & Salt

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Learning Objectives

At the end of the lesson, students should be ableto:

define neutralization

differentiate main properties of acid and base

list the applications of pH control in daily life

define salt

list the types of salt with example describe the uses of salt

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Definition of Neutralization

Base/alkali

Water& Salt

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Acid

Definitions: A chemical substance which ionizes in water to

produce hydrogen ions, H+.

Properties:

Gives a sour taste

Have pH less than 7 Turn blue litmus to red.

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Alkali

Definitions of Alkali: A chemical substance which ionizes in water to

produce free mobile hydroxide ions, OH-.

Properties:

Gives a bitter taste & soapy feeling.

Have pH more than 7 Turn red litmus to blue.

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Base vs Alkali

Base

Solublein water

Alkali

Insolublein water

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Example of Neutralization

Acid + Base/Alkali Salt + Water

H2SO4 (aq)Sulfuric acid

2KOH (aq)Potassiumhydroxide

K2SO4 (aq)Potassium sulfate

H2O (l)

CH3COOH (aq)Ethanoic Acid

NaOH (aq)Sodium hydroxide

CH3COONa (aq)Sodium ethanoate

H2O (l)

2HNO3 (aq)

Nitric acid

CuO (aq)

Copper(II) oxide

Cu(NO3)2 (aq)

Copper(II) nitrate H2O (l)

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Applications of Neutralization

Neutralization

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Agriculture

To treat acidic soil

- Plant cannot growwell in acidic soil.

- Lime fertilizers(powdered

lime/limestone)added to the soil toneutralize the soil.

To treat basic soil

- Treated by usingcompost of rotting

vegetables / leaves.

- rotting vegetables /leaves decomposesto liberate CO2 (g)

acidic gas canneutralize the soil.

To makenitrogenous

fertilizer

-(ammonium

sulfate & ammoniumnitrate)

manufacturedproduced by

neutralization.

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Nitrogenous fertilizer

Sulfuric acid with ammonia solution:

H2SO4 (aq) + 2NH3 (aq) (NH4)2SO4(aq)

Nitric acid with ammonia solution:

HNO3 (aq) + NH3

(aq) NH4

NO3

(aq)

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Industries

To treat acidic effluents

Effluents from electroplating contain acidH2SO4 Treated by adding lime to neutralize before it is discharged into rivers

and stream.

To treat acidic gas

Energy industry power station burn fossil fuels (coal) to produce

electricity. The burning of fossil fuels will liberate SO2 (g) as an acidic pollutant in

the air.

Hence power station used powdered lime/limestone for neutralizationprevent pollution.To prevent coagulation of latex

Rubber industry ammonia solution used to prevent coagulation of

latex. Ammonia solution neutralize lactic acid produced by bacteria in the

latex.To make detergent

Detergent is manufactured in industry through the neutralization ofsulphonic acid with sodium hydroxide solution.

Effluent = liquidwaste materialsthat come out of

factories.

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Treat gastric patient

- Anti acid containing bases (Al(OH)3& Mg(OH)2/

NaHCO3/CaCO3.- Used to neutralize the excess HCl

in the stomach of the gastric solution.

Treat wasp stings

- Wasp sting are alkaline in nature.

- Vinegar is used to cure wasp stingsbecause vinegar can neutralize the

stings.

Treat bee stings- Bee stings and ant bites are acidic

in nature.

They can be neutralized usingalkaline medicine; baking powder.

Prevent tooth decay

- Food stuck between gaps of teeth canbe decomposed by bacteria to produce

lactic acid.

- Acid react with enamel of the teethtrough neutralization to dissolve because

enamel is base.

- Hence, enamel of teeth destroyed by

bacteria in mouth.- Toothpaste component base (Al(OH)3)

Health

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Meaning of Salt

In neutralization of an acid with a base, a salt isformed together with water.

Salt = ionic compound consisting of a cation(metal ion/ammonium ion) which originate from abase that combines with an anion whichoriginates from an acid.

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Salt

Soluble

Can dissolve inwater at roomtemperature

Insoluble

Cannot dissolvein water at

roomtemperature.

Types of Salt

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Solubility of salt

Salts Soluble Insoluble

Nitrate salts All nitrate salts None

Carbonate salts Potassium - K2CO3,

Sodium - Na2CO3,Ammonium(NH4)2CO3

All other carbonate

salts

Chlorides calts All other chloride salts Lead PbCl2,

Silver- AgCl

Sulfate salts All other Sulfate salts Barium BaSO4,Lead PbSO4,Calcium CaSO4

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Applications of Salts

Salt

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Agriculture uses of Salt

Most of the synthetic fertilizer aresalt.

Ammonium sulfate, ammoniumphosphate, ammonium nitrate,potassium chloride, NPK fertilizer.

Syntheticfertilizer

To destroy/kill insects, weeds,pests, fungi.

Copper(II) sulfate, iron(II) sulfate,mercury(I) chloride, sodiumasenate and sodium chlorate (v)

Inorganicpesticides

Increase the agriculture yield.

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Medicinal uses of SaltSalt Uses

Calcium Sulfate Hemihydrate,(CaSO4)2.H2OPlaster of Paris

To make plaster cast supportingbroken

bones. A very hard substance when

hydrated.Iron(II) Sulfate Heptahydrate,FeSO4.7H2O

Iron pills provide iron for patientswho

are suffering from anemia.

Potassium Chloride, KCl Substituent for patient who need alow

intake of sodium salts.

Sodium Hydrogen Carbonate, NaHCO3 Anti-acid neutralize the excess HClin

stomach of a gastric patient.

Barium Sulfate, BaSO4 Examining a patient who is suspect of

havingstomach ulcer.

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Salt uses in Food Industry

Preparationof food

NaCl - flavoring - give saltytaste

Monosodium Glutamate (MSG) flavoring give nice & sweet

taste

Sodium Hydrogen Carbonatebaking powder in the hot wetmixture with acid, release CO2(g) slowly make the cake rise.

Preservationof food

Sodium nitrite, sodiumbenzoate, sodium nitrate,

potassium nitrite, potassiumnitrate

Food can be kept longerwithout getting spoit.

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Salt uses in Chemical Industry

Bleaching agent

Disinfectant

SodiumHypochlorite,

NaOCl

Toothpaste

Water FluoridationTin(II) Fluoride,

SnF2

Washing soda

Make soda lime glass

SodiumCarbonate

decahydrate,Na2CO3.10H2O

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Summary

Neutralization

Definition

Acid/base

Application

Salt

Definition

Soluble/insoluble

Application

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