a
$\underset{\begin{smallmatrix}
\lim iting \\
reagent
\end{smallmatrix}}{\mathop{FeC{{l}_{3}}(aq.)}}\,+\underset{\begin{smallmatrix}
(Excess\,amount) \\
not\,behave\,as
\\
\lim iting\,reagent
\end{smallmatrix}}{\mathop{3NaOH(aq.)}}\,\to $ $Fe{(OH)_3}(s) + 3NaCl(aq.)$
Moles of $Fe(OH)_3$ $ = \frac{{weight\,in\,g}}{{M.\,weight\,of\,Fe{{(OH)}_3}}}$
$ = \frac{{2.14\,g}}{{107\,g/mol}} = 0.02\,mol.$
$1.0$ mole of $Fe(OH)_3$ is obtained from $= 1.0$ mole of $FeCl_3$
$0.02$ mole of $Fe(OH)_3$ is obtained from $0.02$ mole of $FeCl_3$
Molarity
$ = \frac{{No.\,of\,moles}}{{Volume\,in\,L}} = \frac{{0.02\,mole}}{{0.1\,L}} = 0.2\,M$