1. The Chemical Properties of Acids and Bases

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ACIDS BASE AND SALTS

ACIDS:-  

*  These are the substances which have sour taste

• They turn blue litmus solution  red
• They give H⁺ ions in aqueous solution

Type  of acids are as follows →

1. Strong Acid :  Hcl , H₂SO₄
2. Weak Acid : CH₃COOH, HCOOH
3. Concentrated Acid : which have more amount of acid and less amount of water.
4. Dilute Acid : which have more amount of water and less amount of acid

BASES:-    

* These are the substances which have bitter taste and soapy in touch .

• They turn red litmus solution blue
• They give OH^- ions in aqueous solution.

Type of bases are as follows :-

1. Strong Bases :-  NaOH, KOH
2. WEAK BASES :- NH₄OH
3. ALKALI :- These are the bases which are soluble in water (like NaOH,KOH)

SALTS :-  A salts is a substance produced from the reaction of an acid and a base.

FOR EXAMPLE,  NaCl, KCl.

INDICATORS :- The substances that change their colour/ smell when they are added to acidic or alkaline solutions.

Types of Indicators.

1. Natural Indicators :- Litmus , turmeric
2. Synthetic Indicators :-  Phenolphthalein, Mythyl
3. Olfactory Indicators:- Onion, vanilla essence.

CHEMICAL PROPERTIES OF ACID AND BASES.

(i)  Reaction of Metal with :-     

(a)  ACIDS 

Acid   +  Metal      →           Salt +    Hydrogen  gas                      

For Example,

2Hcl           +          Zn       →             ZnCl₂      +    H₂

(Hydrochloric acid) (zinc)       (zinc chloride ) (hydrogen)

(b)  Bases  Base + metal     →   salt + hydrogen gas

For example,

2NsoH         +          Zn    →       Na₃ZnO₂        +        H₂ ↑ 

(sodium hydroxide )  ( zinc)  ( sodium zincate)  ( hydrogen gas )

 Hydrogen gas released can be tested by bringing burning candle near gas bubbles , it burst with pop sound.

(ii)    REACTION OF METAL CARBONATES / Metal Hydrogen carbonates with 

(a)  Acids :- 

(b) Acid   +   metal carbonate/ metal hydrogen carbonate   →  salt + carbon dioxide + water.

  For example :-

1. 2 Hcl + Na₂CO₃        →          2NaCl +  CO₂    +   H₂O
2. HCl +  NaHCO₃         →         NaCl +  CO₂  +H₂O
3. Ca(OH)₂   +   CO₂     →         CaCO₃ +  H₂O

                ( Line Water)                   ( White precipitate )

On passing CO₂  Through lime water , lime water turns milky and in this way CO₂ can be tested.

And when excess CO₂ is passed , milkiness disappers and the following reaction take place.

Passing carbon dioxide gas through calcium hydroxide.

CaCo₃    +    CO₂     +     H₂O    →    Ca (HCO3)

(iii)     Reaction of acids and bases with each other  

Acid     +       base        →       Salt   +    H₂O

Neutralisation Reaction :-   The reaction between an aid and a base to give a salt and water is known as neutralization reaction.

  For Example :-    

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

(iV)  Reaction of Metallic Oxides with Acids  :-

Metallic oxide +  acid     →     salt   +  water

 Metallic oxides are basic in nature

For Example :- 

CaO  + 2HCl    →   CaCl₂   +    H₂O

(v) Reaction of Non- metallic Oxide with base :-

Non- metallic oxide + base    →        salt   +    H₂O 

Non- metallic oxide are acidic in nature.

For Example :-

CO₂   +   Ca(OH)₂    →   CaCO₃  +    H₂O