10 Class- Acids, Bases and Salts part-1

10^th Class Chapter- Acids Bases and Salts

·       Natural indicator of acids and bases – Litmus, Turmeric

·       Synthetic indicator of acids and bases – Methyl Orange, Phenolphthalein

·       Olfactory indicators of acids and bases - Odor of these substance changes in acids and bases.

What is Acid?

Acids are the chemicals which can donate a proton or accept an electron pair in chemical reactions having pH less than 7 and changes color of blue Litmus to red.

Example- HCl, H₂SO₄

What is Base?

Bases are the chemicals which can accept a proton or donate an electron pair in chemical reactions having pH more than 7 and changes color of red Litmus to blue.

Bases which dissolve in water are called as Alkali

Example- NaOH

What is Salt?

Example- NaCl

Acids and Bases Reaction with Metals:-

                   Metal react with acid to form salt.

Acid + Metal ------→ Salt + Hydrogen Gas

Similarly,

Metal react with base to form salt.

Base + Metal ------→ Salt + Hydrogen Gas

Reaction of Metal Carbonates and Metal Hydrogen-Carbonates with Acids:-

Metal carbonates and metal hydrogen carbonates react with acids to form salt, water and carbon dioxide.

Metal Carbonate + Acid --→ Salt + Water + Carbon Dioxide

Example- Na₂CO₃ + 2HCl -→ 2NaCl + H₂O + CO₂

Similarly,

Metal Hydrogen Carbonate + Acid --à Salt + Water + Carbon Dioxide

Example- NaHCO₃ + HCl -→ NaCl + H₂O + CO₂

Reaction of Acids with Bases:-

Reaction of acids with bases to form salt and water is called neutralization reaction.

Acid + Base --→ Salt + Water

Reaction of Acids with Metallic Oxides:-

Acids react with Metallic Oxides to form salt and water.

Acid + Metallic Oxide --→ Salt + Water

Reaction of Bases with Non-Metallic Oxides:-

Non-Metallic Oxides are acidic in nature so these react with bases to form salt and water.

Base + Non-Metallic Oxide --→ Salt + Water

Acids or Bases in Water:-

When acids dissolve in water they produce Hydrogen Ion H⁺(Aq) or Hydronium Ion (H₃O⁺)

HCl + H₂O --→ H₃O⁺ + Cl^-

H⁺ + H₂O --→ H₃O⁺

When bases dissolve in water they produce Hydroxide Ions (OH^-)

NaOH + H₂O ------→ Na⁺(Aq) + OH^-(Aq)

Reactions of Acids or Bases with Water are highly exothermic. Process of mixing Acid or Base with water decrease concentration of ions per unit volume, this process is known as dilution. 

Strength of Acids or Bases:-

Strength of acids depends on number of hydrogen ions (H⁺) produced and strength of bases depends on number of hydroxide ions (OH^-) produced. A universal indicator (present on pH paper) is used to find strength of acids or bases.

10 Class- Acids, Bases and Salts part-2