Reaksi Asam dan Basa

Reaksi \(\ce{NH4Cl}\) dan \(\ce{H2SO4}\)

\begin{equation*}
\begin{array}
&& \ce{2 NH4OH (aq) & + & H2SO4 (aq) & -> & (NH4)2SO4 (aq) & + & 2 H2O (l)} \\\\
\text{mula-mula} & 10 \text{ mmol} && 5 \text{ mmol}  && - && - \\
\text{reaksi} & 10 \text{ mmol} && 5 \text{ mmol}  && 5 \text{ mmol} && 10 \text{ mmol} \\
\text{sisa} & - && - && 5 \text{ mmol} && 10 \text{ mmol}
\end{array}
\end{equation*}

Pada akhir reaksi, terdapat garam \(\ce{(NH4)2SO4}\) sebanyak 5 mmol.

Konsentrasi \(\ce{(NH4)2SO4}\)

\begin{equation*}
\begin{split}
M & = \frac {n}{V} \\\\
M & = \frac {5}{50 + 50} \\\\
M & = 0,05
\end{split}
\end{equation*}

Nilai pH

\begin{equation*}
\begin{split}
\ce{[H+]} & = \sqrt{\frac {Kw \:.\: M}{Kb}} \\\\
\ce{[H+]} & = \sqrt{\frac {10^{-14} \:.\: 0,05 \:.\: 2}{10^{-5}}} \\\\
\ce{[H+]} & = \sqrt{10^{-10}} \\\\
\ce{[H+]} & = 10^{-5} \\\\
\ce{pH} & = 5
\end{split}
\end{equation*}