Question

carrie is conducting an experiment on a solution. the solution’s initial ph is 3.2. then, as carrie gradually adds compound x into the solution, the ph increases to 9.8. which is the most likely identity of compound x?
o a. a strong acid, such as hydrochloric acid (hcl)
o b. a strong base, such as sodium hydroxide (naoh)
o c. a salt, such as sodium chloride (nacl)
o d. a solvent, such as water (h₂o)

Explanation:

1. Analyze the initial pH: The initial pH of the solution is 3.2, which is acidic (since pH < 7).
2. Analyze the final pH: After adding Compound X, the pH increases to 9.8, which is basic (since pH > 7). This means Compound X is a base that neutralizes the acid and makes the solution basic.
3. Evaluate Option A: A strong acid (like HCl) would lower the pH or keep it acidic, not increase it to basic. Eliminate A.
4. Evaluate Option B: A strong base (like NaOH) can neutralize an acid. Adding a strong base to an acidic solution (pH 3.2) would increase the pH, potentially to basic (pH 9.8). This is consistent.
5. Evaluate Option C: A salt (like NaCl) is formed from an acid - base reaction. NaCl solution is neutral (pH ≈ 7). Adding it to an acidic solution would not raise the pH to 9.8. Eliminate C.
6. Evaluate Option D: Water is neutral (pH = 7). Adding water to an acidic solution would dilute it, increasing the pH slightly but not to 9.8 (basic). Eliminate D.

Answer:

B. a strong base, such as sodium hydroxide (NaOH)