Calculate the pH of a $ 20 \%$ solution of the strong base $ NaOH $ (density of the solution = 1.22): What is the mass density of this solution ?
For answers, use (possibly several times) the arrows ↑ Down! and ↓ Up! Complete please this question before moving on to the next one!
$\rho$ $=$ $1.22\frac{g}{mL}$
Calculate the mass of one liter of this solution!
$ m_{1L \; of \; solution} $ $ = $ $ 1.22 \cdot 1000 $ $ = $ $ 1220 \; g $
Calculate the mass of $ NaOH $ in one liter of this solution!
$m_{NaOH}$ $= $ $\frac{20\cdot 1220}{100}$ $=$ $244\;g$
Calculate the number of moles of $ NaOH $ in one liter of this solution! What is the molarity of $OH^-$ ?
$n_{NaOH}$ $= $ $\frac{244}{40}$ $=$ $6.10\;mol$ $[OH^-]$ $=$ $6.10\frac{mol}{L}$
Calculate the pH!
$pH$ $= $ $14+log[OH^-]$ $=$ $14.8$
