Question

Mention the unit of equivalent weight.

Answer 1

Hint: The equivalent weight of a substance is the number of parts by weight of the substance that combines displaces directly or indirectly 8 parts of weight of oxygen and 108 parts by silver.
Unit of any physical quantity is a standard to measure that physical quantity.

Complete answer:
In physical chemistry we do not use any unit to measure the equivalent weight of any atom or molecule.
Equivalent weight simply refers to the amount of any chemical substance. An equivalent of a substance is defined as the amount of it which combines with one mole of hydrogen atom or replaces the same number of hydrogen atoms in a chemical reaction.
Equivalent weight is a very small number which is basically the ratio of weight by valency, so it is a unit less quantity. If it is measured in grams, that equivalent weight is called gram equivalent weight.
Equivalent weight is the amount of substance displaced or liberated by passing 96500Cof electricity. Two or more elements combined or displaced in the mass ratio equal to the ratio of its equivalent weight. Equivalent weight of an element may vary with the variation of its valence.
In a redox reaction equivalent weight of any atom $$\text{=}{\displaystyle \frac{\text{molar}\text{weight}}{\text{change}\text{in}\text{the}\text{oxidation}\text{number}}}$$
$$\text{equivalent}\text{weight}\text{of}\text{an}\text{oxidant}\text{=}{\displaystyle \frac{\text{molar}\text{weight}}{\text{number}\text{of}\text{electron}\text{gained}\text{by}\text{per}\text{molecule}}}$$

Additional information:
Law of equivalence states that in a chemical reaction one equivalent of any substance combines with the one equivalence of another substance.
An element can have more than one value of equivalent weight. For example equivalent weight of $\text{Fe}$ in $\text{FeO}$ and $\text{F}{\text{e}}_{\text{2}}{\text{O}}_{\text{3}}$ is ${\displaystyle \frac{56}{2}}$ and ${\displaystyle \frac{56}{3}}$ respectively.

Note: The factors relating to the equivalent weight in case of acids and bases are basicity and acidity respectively. In the case of oxidants and reductants it is a change in the oxidation number per mole.
$$\text{equivalent}\text{weight}\text{of}\text{an}\text{reducing}\text{agent}\text{=}{\displaystyle \frac{\text{molar}\text{weight}}{\text{number}\text{of}\text{electron}\text{lose}\text{by}\text{per}\text{molecule}}}$$