Question

what happens to the ph of an acidic solution when a base is added?
the ph decreases
the ph increases
the ph remains the same

which of the following solutions is most likely to have a ph of around 9? (think about our lab)
baking soda solution
vinegar
lemon juice
pure water

Explanation:

• For the first question: pH measures acidity (lower pH) or basicity (higher pH). Adding a base to an acidic solution neutralizes some acid, reducing \(H^+\) concentration. By the formula \(pH = -\log[H^+]\), a decrease in \([H^+]\) leads to an increase in pH.
• For the second question: Baking soda (\(NaHCO_3\)) is a weak base. Vinegar (acetic acid) and lemon juice (citric acid) are acidic (pH < 7). Pure water has pH = 7 (neutral). A pH of 9 indicates a weak - base solution, so baking soda solution is correct.

Answer:

• First question: The pH increases
• Second question: Baking soda solution