# Dilution formula for NH3 solution [closed]

I need this for an experiment: ca. 3 mL concentrated (15 M) aqueous ammonia solution, NH3 (from a dropping bottle.)

I have the NH4OH pictured below. How can I dilute it to get what I need? What is the formula?

• The label is a shame, I would not buy products from such a company for serious lab work. May 18, 2023 at 6:45

A solution with a mass fraction of $$25\ \%$$ ammonia corresponds to a concentration of $$c_1=13.32\ \mathrm{mol\ l^{-1}}$$. So obviously you cannot dilute this solution to reach a higher concentration of $$c_2=15\ \mathrm{mol\ l^{-1}}$$, which corresponds to a mass fraction of $$28.5\ \%$$.
Depending on the experiment, however, you could simply use more of the available solution according to \begin{align}n_1&=n_2\\[3pt] c_1V_1&=c_2V_2\\[3pt] V_1&=\frac{c_2V_2}{c_1}\\[3pt] &=\frac{15\ \mathrm{mol\ l^{-1}}\times 3\ \mathrm{ml}}{13.32\ \mathrm{mol\ l^{-1}}}\\[3pt] &=3.4\ \mathrm{ml}\end{align}
Also note that the fictitious substance “ammonium hydroxide” $$(\ce{NH4OH})$$ with a molar mass of $$35.05\ \mathrm{g\ mol^{-1}}$$ (as shown on the label) does not exist.