Question

A certain aqueous solution of $FeC{I}_3$ (formula mass =162) has a density of 1.1g/mL and contains 20.0% $FeC{I}_3$ moral concentration of this solution is.

• A. 0.028
• B. 1.35
• C. 1.27
• D. 1.47

Answer 1

Answer: (C)

1.27

$\text{Here, assume the mass of the solution is 100g.}$

$\text{Given, \% of FeCl₃ in aqueous solution = 20\%}$

$\text{density of solution = 1.1 g/ml}$

$\text{molecular mass of}FeC{l}_3=56+3\times 35.5=56+106.5=162.5g/mol$

we have,

$\text{Molarity(M)}=\frac{wt.\times 1000}{Mol.wt\times Volume\left(ml\right)}$

$M=\frac{20\times 1000}{162\times \frac{100}{1.1}}$ $\because V=\frac{w}{d}=\frac{100}{1.1}ml$

$=1.35M$

$\text{Hence, the correct option is B}$