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

\( = \frac{{No.\,of\,moles}}{{Volume\,in\,L}} = \frac{{0.02\,mole}}{{0.1\,L}} = 0.2\,M\)