Question

A certain aqueous solution of $FeC{l}_3$ [formula mass $=162]$ has a density of $1.1g/mL$ and contains $20.0\%FeC{l}_3.$ Molar concentration of this solution is

• A. 0.028
• B. 0.163
• C. 1.357
• D. 1.47

Answer 1

Answer: (C)

20% FeCl₃ solution means 100 g of solution contains 20 g FeCl₃ .
$\Rightarrow$ Volume of 100 g solution $=\frac{100g}{1.1g/mL}$
$=90.91mL$
Moles of 20 g FeCl${}_3=\frac{20}{162}=0.1234$ mole
$\Rightarrow$ Molar concentration of solution
$=\frac{0.1234}{90.91}\times 1000$
$=1.357$ M