acid base and salt class 10 notes

Aditya Raj Anand

Sunday 1 March 2020

science class 10

acid base and salt class 10 notes

There are 150 different kinds of chemical ingredients are known us at present. When these elements combine to form a large number of compounds. these compounds can be classified  on the basis of chemical properties into three groups.

1. Acid
2. Base
3. Salt

In this notes we will study all the three types of compounds acid base and salt in detail but we start with acid and base letter will discuss about salt in more detail and easy language as possible.

What is acid?

• those chemical substance that are sour in taste and change the colour blue litmus to red.

• The word acid is derived from the Latin word a serious means sour in taste.

• Acid are mostly obtained from natural resources.

• The acid obtained from minerals of the earth are called mineral acid.

• Mineral acid also called inorganic acid example sulfuric acid, hydrochloric acid, nitric acid etc.

• The acid obtained from plants and animals are called organic acid example of formic acid, citric acid, acetic acid, lactic acid etc.

Concentration of acid:-

It means that amount of water present in the given sample of acid solution in water.

On the basis of concentration of acid:-

1. Concentrated acid
2. Dilute acid

Physical properties of acid:-

• It is sour in taste.
• Its colour change Blue litmus to red.
• It conduct electricity.

Arrhenius concept of acid:-

• It gives H + ions in aqueous solution.

Example KOH, NaOH, Ca(OH)2 etc.

• the base which are completely ionized to give OH minus ions are called strong base.

Example NaOH, KOH.

• Abhi speech on partially ionized to give OH ions are called weak base.

Chemical properties of base:-

• When base react with some metal then hydrogen gas is evolved.

NaOH + Zn = Na2Zno2 + H2

• When base react with acid then salt and water are formed.

NaOH + HCl = NaCl + H2O

• Base combine with ammonium salt to give ammonia.

NaOH + NH4Cl = NaCl + H2O + NH3

Uses of some common base:-

Sodium hydroxide
It is used in manufacturing of soap, artificial fibres like rheon and in paper industries.

Potassium hydroxide
Reducing industries of soap observing co2 etc.

Calcium hydroxide
PUC manufacturing industries of bleaching powder in white washing and testing of co2 gas.

Magnesium hydroxide
It is anti acid to neutralize acid in the stomach.

Ammonium hydroxide
It is used for removing grease from cloth in dry cleaning and in cleaning window panels.

pH scale:-

• A measure of acidity or alkalinity of water soluble substance.

• The pH value is a number from 1 to 14.

• It has no unit.

• the strength of an acid or base is measured on a scale of number called the pH scale.

• The pH scale measure how is acidic or basic substance is.

• A substance that is neither acidic or basic is neutral.

Universal indicator:-

The colour produced by universal indicator paper at various pH values are shown in the chart given below.

this pH colour chart shows how the colour of universal indicator paper changes with solution of different pH values.

Water will produce a given colour with universal indicator.

we can however measure the strength of an acid solution or basic solution by using a special type of indicator call universal indicator which works by measuring the pH of a solution.

to obtained an idea of how is acidic or basic substance is universal indicator is used.

Lower the pH stronger the acid.

Higher the pH stronger base.

Salt:-
It is the ionic compound in which have positive ions but not h + ions and negative ions but not OH minus ions.

Acid + base = salt + water
HCl + NaOH = NaCl + H2O

Types of salt:-
Normal salt
Acidic salt
Basic salt
Mixed salt
Double salt

Normal salt:-
a normal salt is formed when all the hydrogen ions or h + ions of an acid have been replaced by metal ions or ammonium ions.
Example HCl + NaOH = NaCl + H2O
Here metal ions Na+ replaced H+ ions with the combine of CL minus completely so this reaction normal salt is formed.

Some example of normal salt are HCl, KCl, MgCl2, AlCl2 etc.

Acidic salt:-
this salt formed by partial replacement of h + ions of an acid by metal ions or ammonium ions.
Example NaHSo4, KHSo4 etc.

Basic salt:-
The salt is formed by the partial neutralization of a base by an acid.
Example Cu(OH)No3, Pb(OH)NO3, Pb(OH)CL etc.

Mixed salt:-
the salt containing more than one cation or anion other than h plus or minus ions are called mixed salt.

Double salt:-
double salts are salts containing more than one cation or anion are obtained by combination of two different salts which wire crystallized in the same regular ionic latics.

pH of salt:-
salt may be acidic, basic or neutral depending upon the acid or base therefore salt maybe different PH value.

Salt of strong acid and strong base or neutral with PH value of 7.

Salts of strong acid and weak base are acidic with PH value less than 7.

Salt of weak acid and strong base are basic with PH value more than 7.