Equivalent mass of salt

When atoms combine to create chemical compounds, the elements are always present in exact amounts by mass. This fact may be utilised to make chemically distinct molecules with different masses equal. The equivalent mass is used in general chemistry, volumetric analysis, gravimetric analysis and polymer chemistry.

According to the laws of chemical combination, all elements combine. The value of the equivalent mass of an element is the number of parts it mixes with 1 part by mass of Hydrogen, eight parts by mass of oxygen, 35.5 parts by mass of Chlorine, or one gram equivalent of any other element.

The valency of an element determines its equivalent mass. The formula for calculating an element’s equivalent mass is given as –

Equivalent mass of salt = molecular mass of the salt

                                total positive valency of metal atoms

The mass of a simple salt that contains one grams equivalent of the metal or a radical is called its equivalent mass. 

The number of parts by mass of a salt formed by neutralising one equivalent of an acid by a base is its equivalent mass. 

The salt is generated by neutralising one equivalent of an acid by a base.

Divide the molar mass of an acid by the number of protons to find the Equivalent mass of Acid and base. You can also simply divide the molar mass of the base by the number of hydroxyl groups to get the equivalent mass. 

Material is formed when an acid reacts with a base. The positive ion (cation) of a base and the negative ion (anion) of acid make up a grain of salt. A neutralisation reaction occurs when an acid reacts with a base.  

The mass of a simple salt that contains one grams equivalent of the metal or a radical is called its equivalent mass. 

The idea of equivalent mass to compare chemically different elements! Atoms combine to form chemical compounds. The elements are always present in definite proportions by mass, and this property can be used to make chemically different molecules with different masses. 

Here, in the equivalent mass of salt, the idea is to compare chemically made different compounds of salts. Salts are formed when acid and base react.

Equivalent mass of salt is given as : 

Equivalent mass of salt = molecular mass of the salt

                                                    total positive valency of metal atoms.

• Consider some examples for equivalent mass of salt 

Example 1 :  Suppose KCl, (Potassium Chloride)

In the case of salt like potassium chloride, the salt formed by the neutralisation of one equivalent of an acid by a base.

KOH + HCl → KCl + H2O

Therefore, the equivalent mass of the salt is equal to its molar mass.

Here molecular mass of K (potassium) is 39, whereas molecular mass of Cl (chlorine) 35.5, so molecular mass for the compound KCl is  

K + Cl = Total Molecular Mass

Therefore, 39 + 35.5 = 74.5 

Here, in the case of KCl, it contains 1g equivalent of Potassium(K) and 1g equivalent of Chlorine (Cl)

Hence, Equivalent mass of KCl is 74.5/1 = 74.5

Example 2 : Consider AlCl3(Aluminium Chloride)

Where, AlCl3= 27 + 35.5 * 3, which is equal to 133.5

In the case of AlCl3, it contains 1 gram equivalent of Al and 3 gram equivalent of Cl 

Therefore, Equivalent mass of Alcl3 is 133/3= 44.5  

Example 3 : Na2CO3(Sodium Carbonate)

Here Na2CO3  reacts with with HCL as

Na2CO3 + 2HCl → 2 NaCl + CO2 + H2O

Molecular mass  of Na2CO3 = 23*2 + 12*1 + 16*3=106

Here, 1 gram equivalent of Na2CO3 Reacts with 2g equivalent of HCl. Therefore equivalent mass of Na2CO3 is 106/2 = 53

Another method for solving the same

Here, Na2CO3  ionises to produce 2Na+ and CO3-2, as shown the charge on both ions is 2.

Since sodium carbonate Na2CO3  contains two atoms sodium, an atom of carbon(C) and 3 atoms of Oxygen (O)

The molecular weight for compounds is

                            Na: 2 * 23.0 which is equal to 46

                                     C: 1 * 12.0 which is equal to 12

                                     O: 3*16  which is equal to 48

When we add these values 46+12+48 which is equal to 106

Therefore 106 g/mole is the molar mass of Na2CO3 

Equivalent weight of Na2CO3 = 106/2 = 53 g/eq

Consider Al2(SO4)3 and try solving by the same method

Conclusion:

The Equivalent mass of salt is the weight of a simple salt containing one gramme of a metal or radical. When an acid and a base react, salts are created. When an acid combines with a base to form a salt, a neutralisation reaction occurs.

The equivalent mass of a salt is equal to its molar mass. In the case of potassium chloride, it is formed by the neutralisation of one equivalent of an acid by a base. AlCl3(Aluminium Chloride) contains 1 gram equivalent of Al and 3 grams equivalent of Cl.

Equivalent mass of salt = molecular mass of the salt

                                                    total positive valency of metal atoms