Equivalent mass is sojmething that helps you decide relatively, that to what extent will different elements react with a given quantity ( fixed no. of moles n mass etc) of a given element or compd...

 

Hence, 35.5 gm (1 mole) of Chlorine will react the same as will 16gms (1/2 a mole) of Oxygen and so on, with any other element, say X with valency say v+ or v-.

 

This also explains that chlorine reacts as Cl₂ molecule to attach 2 Cl^- ions to the third element, while oxygen, though reacting as O₂ molecule, will add only one O^2- ion to the same element....as the no. of electrons required by the third element will remain the same, and so the anion/element being added to it should have the same charge that's required to balance the charge on it...

 

Similarly u get 2gm of Hydrogen reacting with the same compd...

 

 

and hence we define it as....

 

no. of moles divided by charge on each mole....    (n/c)

(infact better to say, charge per mol....(c/n)...)

and in terms of mass... (M * c) /n

 

so u get the equivalent mass for one mol ( since we r takin PER MOLE) as:
(M)/n....where M is the molecular mass and n is the element's valency...

 

the value of electrons being given changes for acids basis etc n is different from that of the valency so, we replace valency by something called n-factor, ie actually the total no. of electrons that acid/base can give...

 

so that gives M divided by n-factor...

 

type jaldi jaldi kiya...so i might have typed something wrong....i mean spellin errors n all....so jus ignore them...n chill !

in simple wrd

equivalent mass is d mass wich combines wid or displaces one part bt d weight of hydraogen ,8 part by d weight of oxygen.....and 35.5 part bt d weight of cholrine