Question

A certain aqueous solution of $FeCl _{3}$ [formula mass $=162]$ has a density of $1.1 g / mL$ and contains $20.0 \% FeCl _{3} .$ Molar concentration of this solution is

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

Answer 1

Answer: (C)

1.357

Answer 2

20% FeCl solution means 100 g of solution contains 20 g FeCl . $\Rightarrow$ Volume of 100 g solution $=\frac{100\,g}{1.1\,g/mL}$ $=90.91 \,mL$ Moles of 20 g FeCl$_{3}=\frac{20}{162}=0.1234$ mole $\Rightarrow$ Molar concentration of solution $=\frac{0.1234}{90.91}\times1000$ $=1.357$ M