\( \mathrm{pOH}=7.0 \) Express your answer using one decimal place.

Atomic weight \( (\mathbf{A W})=\sum \) isotopic mass \( \times \) aboundance \( \cdot \) Naturally occurring carbon comprises \( \mathbf{9 8 . 9 3 \%} \%{ }^{12} \mathrm{C} \) and \( \mathbf{1 . 0 7 \%}{ }^{13} \mathrm{C} \). The masses of these isotopes are \( \mathbf{1 2} \) amu \( ( \) exactly and \( \mathbf{1 3 . 0 0 3 3 5} \mathrm{amu} \), respectively, making the atomic weight of carbon. The atomic weights of the elements are listed in the periodic table. atomic weight of \( \mathbf{C}=(\mathbf{1 2})(\mathbf{0 . 9 8 9 3})+(\mathbf{1 3 . 0 0 3 3 5})(\mathbf{0 . 0 1 0 7})=\mathbf{1 2 . 0 1} \) atomic weight of \( \mathbf{C}=(\mathbf{1 2} \times \mathbf{9 8 . 9 3} \%)+(\mathbf{1 3 . 0 0 3 3 5} \times \mathbf{1 . 0 7} \%) \) \( =\mathbf{1 2 . 0 1} \)

(8)In which of the following solution, the concentration of acid is equal to the concentration of hydronium ion? \( \begin{array}{llll}\text { a) } \mathrm{HCN} & \text { b) } \mathrm{HCOOH} & \text { c) } \mathrm{H}_{2} \mathrm{SO}_{4} & \text { d) } \mathrm{HBr}\end{array} \)

\( \mathrm{pOH}=7.0 \) Express your answer using one decimal place.

\( \mathrm{NH}_{4} \mathrm{OH} \) \( \begin{array}{l}\text { strong } \\ \text { weak }\end{array} \)

\( \mathrm{HI}(a q) \) and \( \mathrm{NaOH}(a q) \) Express your answer as a balanced chemical equation. Identify all of the phases in your answer.