For each of the following cases, decide whether the pH is less than 7 , equal to 7 , or greater

step 1 For the first solution, all of the acetic acid will be neutralized with potassium hydroxide. The

For each of the following cases, decide whether the pH is...

For each of the following cases, decide whether the $\mathrm{pH}$ is less than 7 , equal to 7 , or greater than 7 . (a) Equal volumes of $0.20 \mathrm{M}$ ammonia, $\mathrm{NH}_3$, and $0.20 \mathrm{M} \mathrm{HCl}$ are mixed. (b) Equal volumes of $0.10 \mathrm{M}$ acetic acid, $\mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H}$, and $0.10 \mathrm{M} \mathrm{KOH}$ are mixed. (c) $25 \mathrm{~mL}$ of $0.015 \mathrm{M} \mathrm{NH}_3$ is mixed with $12 \mathrm{~mL}$ of $0.015 \mathrm{M} \mathrm{HCl}$. (d) $150 \mathrm{~mL}$ of $0.20 \mathrm{M} \mathrm{HNO}_3$ is mixed with $75 \mathrm{~mL}$ of $0.40 \mathrm{M} \mathrm{NaOH}$. (e) $25 \mathrm{~mL}$ of $0.45 \mathrm{M} \mathrm{H}_2 \mathrm{SO}_4$ is mixed with $25 \mathrm{~mL}$. of $0.90 \mathrm{M} \mathrm{NaOH}$.

For each of the following cases, decide whether the $\mathrm{pH}$ is less than 7 , equal to 7 , or greater than 7 .
(a) Equal volumes of $0.20 \mathrm{M}$ ammonia, $\mathrm{NH}_3$, and $0.20 \mathrm{M} \mathrm{HCl}$ are mixed.
(b) Equal volumes of $0.10 \mathrm{M}$ acetic acid, $\mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H}$, and $0.10 \mathrm{M} \mathrm{KOH}$ are mixed.
(c) $25 \mathrm{~mL}$ of $0.015 \mathrm{M} \mathrm{NH}_3$ is mixed with $12 \mathrm{~mL}$ of $0.015 \mathrm{M} \mathrm{HCl}$.
(d) $150 \mathrm{~mL}$ of $0.20 \mathrm{M} \mathrm{HNO}_3$ is mixed with $75 \mathrm{~mL}$ of $0.40 \mathrm{M} \mathrm{NaOH}$.
(e) $25 \mathrm{~mL}$ of $0.45 \mathrm{M} \mathrm{H}_2 \mathrm{SO}_4$ is mixed with $25 \mathrm{~mL}$. of $0.90 \mathrm{M} \mathrm{NaOH}$.

Key Concepts

Buffer Solutions

Buffer systems arise when a weak acid and its conjugate base, or a weak base and its conjugate acid, are present in appreciable amounts. Buffers resist changes in pH even when small amounts of acid or base are added, and understanding their formation is crucial when mixing weak acids or bases with their counterparts.

Stoichiometry and Reaction Extent

Using the molarity and volume of the reactants allows calculation of the number of moles, thereby determining if the acid-base reaction completely neutralizes the reacting species or if there is an excess of either acid or base. This calculation is central to predicting the resulting pH of the mixture.

Acid-Base Neutralization

This concept involves the reaction between acids and bases to form water and a salt. Determining whether the solution is acidic, neutral, or basic depends on whether either the acid or base is in excess after the reaction. The pH is dictated by the concentration of excess hydrogen ions (H?) if an acid remains or hydroxide ions (OH?) if a base remains.

Strong versus Weak Acids and Bases

The strength of an acid or base indicates its degree of ionization in water. Strong acids and bases dissociate completely, making the determination of excess H? or OH? straightforward, while weak acids and bases only partially dissociate, which may lead to additional considerations such as buffer formation.

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