Tuesday 21 May 2019

Class 10 - Chemistry - Chapter - Acids and Bases - Keys Points To Remember (#class10Chemistry)(#cbsenotes)(#eduvictors)

 Acids and Bases 
Class 10 - Chemistry 
(Important Points To Remember)

Class 10 - Chemistry - Chapter - Acids and Bases - Keys Points To Remember (#class10Chemistry)(#cbsenotes)(#eduvictors)

Acids are the substances which taste sour, change blue litmus red, are corrosive to metals and furnish H⁺ ions in their aqueous solutions.

Bases are the substances which taste bitter, change red litmus blue, feel slippery and furnish OH⁻ ions in their aqueous solutions.

Acid-base indicators are dyes or mixtures of dyes which are used to indicate the presence of acids and bases.

Indicators are the substances that show one colour in an acidic medium and another colour in a basic medium. Litmus, phenolphthalein and methyl orange are commonly used indicators. Onion, Vanilla extract and Clove oil are olfactory indicators.

Acids are presents in many unripe fruits, vinegar, lemon, sour milk etc., while bases are present in lime water, window pane cleaners, many drain cleaners etc.

When an acid reacts with a metal, hydrogen gas is evolved and a corresponding salt is formed.

When a base reacts with a metal, along with the evolution of hydrogen gas a salt is formed which has a negative ion composed of the metal and oxygen.

  Living beings carry out their metabolic activities within an optimal pH range.

Aqueous solutions of acids and bases both conduct electricity as they dissociate on dissolving in water and liberate cations and anions which help in conducting electricity.

Strong acids and bases dissociate completely in water.

Weak acids and bases dissociate  partially in water.

Acids and bases react with each other to produce salt and water. Such reactions are called neutralization reactions.

Mixing concentrated acids or bases with water is a highly exothermic process.

Water itself undergoes dissociation and furnishes H⁺ and OH– ions in equal numbers. This is called self dissociation of water.

In pure water [H⁺] = [OH⁻]. It is also true in any neutral aqueous solution. In terms of pH, pH = pOH = 7 in water and any neutral solution.

In acidic solution [H⁺] > [OH⁻] and pH < pOH. Also pH < 7 at 25°C.

In basic solutions [H⁺] < [OH⁻] and pH > pOH. Also pH > 7 at 25°C.

If pH of rain water falls below 5.6, it is called acid rain and is quite harmful.

☛See Also:

No comments:

Post a Comment

We love to hear your thoughts about this post!

Note: only a member of this blog may post a comment.