pH Classification of Solutions

Steps:

• Identify ammonia as a weak base (0.1 mol/dm³ yields pH ≈11 due to partial ionization).
• Identify hydrochloric acid as a strong acid (0.1 mol/dm³ yields pH=1 from [H⁺]=0.1).
• Identify sodium chloride as a neutral salt (pH=7, no hydrolysis).
• Match order: ammonia (11), hydrochloric acid (1), sodium chloride (7), sodium hydroxide (13, strong base with [OH⁻]=0.1, pH=14-pOH=13).

Why C is correct:

• It assigns pH values matching acid-base strength: weak base (11), strong acid (1), neutral (7), strong base (13) per pH = -log[H⁺] or 14 + log[OH⁻].

Why the others are wrong:

• A: Lists five values instead of four for the substances.
• B: Incorrect order starts with acid (1) instead of base (11).
• D: Reverses assignments, placing strong base (13) first for ammonia.

Final answer: C