An aqueous solution that is `30.0%` NaOH by mass has a density of `1.33"g mL^(-1)`.What is the molarity of NaOH in this solution?

Options

A. 0.028
B. 0.135
C. 1.27
D. 1.47

Answer

B

Explanation

Vol. Of `FeCl_(3)=20mL`
Density = `("Mass")/("Volume")`
`1.1g//mL=("Mass")/(20)`
implies Molar mass of `FeCl_(3)=162.2g//mol`
number of moles of `FeCl_(3)=("Given mass")/("Molar mass")`
`=(22g)/(162.2g//mol)=0.135` moles
Hence, molar concentration of 20 mL
`FeCl_(3)` in 1L of solution = 0.135 mol/L.