Question

Write the formula and calculate the molar mass of ferric chloride.

Answer 1

Hint: Ferric chloride is an inorganic compound.It consists of two elements one is iron ($\text{Fe}$) and chlorine ($\text{Cl}$). It is generally prepared from ferrous chloride by the action of chloride or nitric acid. And it is widely used in water purification and for sewage treatment.

Complete step by step answer:
It is already said that Ferric chloride is an inorganic compound, with a formula of $\text{FeC}{\text{l}}_3$. Consisting of one $\text{Fe}$ atom and three $\text{Cl}$ atoms. Ferric chloride iron is in $+3$oxidation state. It is also known as molysite.
The molar mass is the mass of a given molecule or compound, it is measured in $\text{g}\text{mo}{\text{l}}^{-1}$. The characteristic molar mass of an element is atomic mass in $\text{g}\text{mo}{\text{l}}^{-1}$. It can also be calculated by multiplying atomic mass in $\text{amu}$ with Avogadro number. In order to calculate the molar mass of a compound having multiple atoms we have to take the sum of all the atomic mass of constituent atoms.
Here in $\text{FeC}{\text{l}}_3$, we can calculate the molar mass by taking the sum of atomic mass of one $\text{Fe}$ atom and three $\text{Cl}$atoms. Atomic mass of $\text{Fe}$ atom is given by $55.8\text{g}$ and that of $\text{Cl}$ is $\text{35}\text{.5}\text{g}$. In $\text{FeC}{\text{l}}_3$ there is one $\text{Fe}$ atom and three $\text{Cl}$ atoms.
Molar mass of $\text{FeC}{\text{l}}_3$= $55.8\times \left(3\times 35.5\right)=162.3\text{g}\text{mo}{\text{l}}^{-1}$.
Molar mass of ferric chloride is $162.3\text{g}\text{mol}{}^{-1}$
Since molar mass is mass in grams of one mole of an element its unit is $\text{g}\text{mo}{\text{l}}^{-1}$

Note:
Ferric chloride is harmful, highly corrosive and acidic. The anhydrous ferric chloride can be used as a powerful dehydrating agent. It has industrial uses like manufacture of pigments, sewage treatment and water purification. Anhydrous iron chloride is a strong Lewis acid that is used as a catalyst for organic synthesis.