# Question 19f01

Jul 19, 2017

%"mass NaOH" = 32%

#### Explanation:

I'll assume the percentage concentrations are those by mass.

We know:

• there are $8.6$ $\text{kg}$ of water

• there are $3.4$ $\text{kg}$ of caustic soda

Since the caustic soda is 92.7% $\text{NaOH}$ by mass, the mass of $\text{NaOH}$ in solution is

$\left(0.972\right) \left(3.4 \textcolor{w h i t e}{l} \text{kg}\right) = 3.30$ $\text{kg NaOH}$

The percent by mass in solution is

%"mass NaOH" = "mass NaOH"/"mass solution"xx100%

= (3.30color(white)(l)"kg")/(underbrace(3.4color(white)(l)"kg")_"caustic soda" + underbrace(8.6color(white)(l)"kg")_"water")xx100%

= color(red)(32%#

rounded to $2$ significant figures.