Question

What is the equivalent weight of potassium dichromate in an acidic medium?

Answer 1

Hint: Recall the formula of equivalent weight from the chapter mole concept and find the change in number of electrons of potassium dichromate in acidic medium.

Complete step by step answer:
Potassium dichromate in an acidic medium is a strong oxidizer. It means it gains electrons during redox reaction.
${ K }_{ 2 }{ Cr }_{ 2 }{ O }_{ 7 }$ in solution gives following ions -
${ K }_{ 2 }{ Cr }_{ 2 }{ O }_{ 7 } + { 14H }^{ + } + 6e- \rightarrow { 2K }^{ + } + { 2Cr }^{ 3+ } + { 7H }_{ 2 }O$
Molecular weight of potassium dichromate = 294 g/mol
There is overall gain of 6 electrons.
That means n-factor for this reaction is 6.
$Equivalent\quad weight\quad =\quad \dfrac { molecular\quad weight }{ n }$
Now putting values in the above equation.
We will get the final value of equivalent weight = 49 g/mol.

Additional information:
Potassium dichromate, is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications.

Potassium dichromate is an oxidizing agent that is milder than potassium permanganate. It is used for the oxidation of alcohol. This converts primary alcohols into aldehydes and carboxylic acids under more pressing conditions.
It is highly corrosive and is a strong oxidizing agent for which it is used in wood preservatives, pigments manufacture and photochemical processes.

Note: Equivalent weight is the mass of one equivalent, that is the mass of a given substance which will combine with or displace a fixed quantity of another substance.