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vedantu_anubhagaur
Home Work Rockers
Home Work Rockers
Classification Of Compounds
Acids Salts
Bases
Definition of an acid
Acids are the chemical substances which turn blue litmus red and
when dissolved in water, dissociate to give H+ ion
HCl + H2O ⟶ H+(aq) + Cl-(aq)
General properties of an acid
● Acids are sour in taste
● turn blue litmus red
● corrosive in nature● dissociates into H+ ions in
water
Definition of A base
Bases are the chemical substances which turn red litmus blue and
when dissolved in water, dissociate to give OH- ion
NaOH + H2O ⟶ Na+(aq) + OH-
(aq)
Bases
General properties of a base
● Bases are bitter in taste
● turn red litmus blue
● feel soapy/soft to touch● dissociate to give OH- when
dissolved in water.
Important note:
All bases are not soluble in water.
Bases which are soluble in water arecalled alkali.
Salts
How can we define a Salt
They are formed when an acid reacts with a base.
NaOH + HCl ⟶ NaCl + H2O
Indicators
● substances that are used to testwhether a substance is acidic orbasic or neutral in nature.
● They change their color whenadded to a solution containingan acidic or a basic substance.
Indicators
Onion , Vanilla Extract & Clove as Indicator
AGPRO
CHEMICAL PROPERTIES OF ACIDS AND BASES
Reaction of an Acid with Metals
Reaction of Zinc With Dil H2SO4
Acid + Metal → Salt + Hydrogen gas
Reaction of an Base with Metals
2NaOH + Zn → Na2ZnO2 + H2
Reaction of an Metal Carbonates with Acids
Reaction of Sodium Carbonate with HCl
Na2CO3(s) + 2HCl(aq) → 2NaCl(aq) + H2O(l) + CO2(g)
Reaction of Sodium BiCarbonate with HCl
NaHCO3(s) + HCl(aq) → NaCl(aq) + H2O(l) + CO2(g)
Reaction of an Metal Carbonates with Acids
On passing the carbon dioxide gas evolved through lime water
Ca(OH)2(aq) + CO2(g) → CaCO3(s) + H2O(l)(Lime. water)
(White precipitate)
CaCO3(s) + H2O(l) + CO2(g) → Ca(HCO3)2(aq)
(Soluble in water)
Reaction of Acids & Bases
Base + Acid → Salt + Water
NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
Reaction of Acids & Bases
Neutralisation Reaction
The reaction between an acid and a base to give a salt and water is known
as a neutralisation reaction
Reaction of metallic Oxides with Acids
Metal oxide + Acid → Salt + Water
NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
WHAT DO ALL ACIDS AND ALL BASES HAVE IN COMMON?
● Acid or base solution in water conducts electricity.
● Acid or base, dissociates into ions when added in water.
HCl + H2O ⟶ H3O+ + Cl-
NaOH + H2O ⟶ Na+(aq) + Cl-(aq)
Can we add water Directly Into Acid ?
The process of dissolving an acid or a base in water is a highly
exothermic one.
What to do ?
If water is added to a concentrated acid, the heat generated may cause the mixture to splash out and cause
burns.
Dilution
● Mixing an acid or base with water results in decrease in the concentration of ions (H3O+/OH– ) per unit volume.
● Such a process is called dilution and the acid or the base is said to be diluted.
HOW STRONG ARE ACID OR BASE SOLUTIONS?
Strength of an acid
➢ The more will be the H+ iondissociated, the stronger will be theacid.
➢ The dissociation of H+ ion in waterdepends on the strength of the bondbetween hydrogen and othercomponent.
➢ The stronger will be the bond,the lesser will be the dissociationand vice versa.
➢ Therefore HCl is more acidic thanH2SO4
Strength of an acid
Strength of a base
➢ the more will be the OH- iondissociated, the stronger will be thebase.
➢ We can do this by making use ofa universal indicator, which is amixture of several indicators.
➢ The universal indicator showsdifferent colours at differentconcentrations of hydrogen ionsin a solution.
Strength of an acid or a base
pH Scale
pH Scale
Importance of pH in Everyday Life
● Our body works within the pH range of 7.0 to 7.8.
● Plants require a specific pH range for their healthy growth.
Importance of pH in Everyday Life
● Our stomach produces hydrochloric acid which helps in the digestion of food without harming the stomach.
● Tooth decay starts when the pH of the mouth is lower than 5.5.
● Bee-sting leaves an acid which causes pain and irritation.
● Salts having the same positive ornegative radicals are said tobelong to a family.
Family of salts
● Acidic Salts : Copper chloride● Basic Salts : Sodium bicarbonate● Neutral Salts : Sodium chloride
pH of salts
The common salt is an important rawmaterial for various materials such assodium hydroxide, baking soda,washing soda, bleaching powder andmany more.
Common salt — A raw material for chemicals
Method of preparation:
Chlor-alkali process
2NaCl + 2H2O → 2NaOH + Cl2 + H2
(aq) (l) (aq) (g) (g)
1. Sodium Hydroxide
● used for making soaps,
detergents.
● used for making papers
● used for making pesticides, PVC,
disinfectants.
Uses of Sodium Hydroxide
● Bleaching powder is representedas CaOCl2 , though the actualcomposition is quite complex.
● Ca(OH)2 + Cl2 → CaOCl2 + H2O
2. Bleaching powder
● used for bleaching cotton and
linen in the textile industry.
● as an oxidising agent in many
chemical industries
● used for disinfecting drinking
water to make it free of germs.
Uses of Bleaching powder
● The chemical name of the compound is sodium hydrogencarbonate (NaHCO3 ).
● Manufacture of Baking soda:
Solvay Process:
3. Baking Soda
● It is produced using sodiumchloride as one of the rawmaterials.
NaCl + H2O + CO2 + NH3⟶ NH4Cl + NaHCO3
3. Baking Soda
● in the making of baking powderwhich is used in making cakes.
● Sodium hydrogencarbonate is alsoan ingredient in antacids.
Uses of Baking Baking Soda
● Recrystallisation of sodiumcarbonate gives washing soda.
● It is a basic salt
4. Washing soda
● Na2CO3 + 10H2O⟶ Na2CO3.10H2O
Washing soda
Washing soda
Washing soda
● Washing soda is used in paperindustries.
● used in soap industries.● used as a cleaning agent for
domestic purposes.● for removing permanent hardness of
water.
Washing sodaUses of Washing soda
The water of crystallization meanshaving a fixed number of moleculespresent in one formula of a unit of salt.
Water of crystallisation
● The water of crystallization iscaused by forming purifiedcrystals from an aqueous solution.
● On heating these compounds thehydrated water is removed
Example:Chemical formula for hydratedcopper sulphate is CuSO4.5H2O.
Water of crystallisationWater of crystallisation
Example:
Fig. heating copper sulphate
➢ The chemical formula for gypsumis CaSO4 .2H2O
➢ It has two water molecules aswater of crystallisation.
Gypsum
Gypsum
➢ The chemical formula of plaster ofparis is CaSO4.½H2O
➢ On heating gypsum at 373 K, itloses water molecules andbecomes calcium sulphatehemihydrate (plaster of paris).
Plaster of paris
● used as plaster for supportingfractured bones in the rightposition.
● used to make sculptures andused as decorative in buildings.
● as a coating on wood and metalstructures to avoid any fireaccidents
Uses of Plaster of paris
Name the natural source of each of
the following acid
(i) Citric acid. (ii)Oxalic acid.
(iii)Lactic acid. (iv)Tartaric acid.
Home Work
Acids Bases &
Salts
One Shot
Explanation
This Session
AGPRO
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