Identify the solution that would have a pH value equal to a.7 b.14

Question 1: Identify the solution that would have a pH value equal to 7.

A solution with a pH value of 7 is considered neutral. Examples include:

• Pure water at $25^\circ\text{C}$.
• A solution of a salt formed from a strong acid and a strong base, such as sodium chloride ($\ce{NaCl}$) or potassium nitrate ($\ce{KNO3}$) dissolved in water.

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Question 2: Identify the solution that would have a pH value equal to 14.

A solution with a pH value of 14 is extremely basic (alkaline). An example is:

• A 1.0 M solution of a strong monohydroxide base, such as sodium hydroxide ($\ce{NaOH}$) or potassium hydroxide ($\ce{KOH}$).
  • Step 1: Calculate pOH for a 1.0 M strong base. For a strong base like $\ce{NaOH}$, it dissociates completely: $\ce{NaOH(aq) -> Na+(aq) + OH-(aq)}$. If $[\ce{NaOH}] = 1.0\ \text{M}$, then $[\ce{OH-}] = 1.0\ \text{M}$. $$\text{pOH} = -\log[\ce{OH-}]$$ $$\text{pOH} = -\log(1.0)$$ $$\text{pOH} = 0$$
  • Step 2: Calculate pH from pOH. At $25^\circ\text{C}$, $\text{pH} + \text{pOH} = 14$. $$\text{pH} = 14 - \text{pOH}$$ $$\text{pH} = 14 - 0$$ $$\text{pH} = \boxed{14}$$