Which aqueous solution turns phenolphthalein pink? (A) HCl (B) NaCl - HSC - SSCE Chemistry - Question 9 - 2007 - Paper 1

Phenolphthalein is an acid-base indicator that turns pink in basic (alkaline) solutions. Aqueous solutions of hydrochloric acid (HCl) are acidic and would not turn phenolphthalein pink. In contrast, sodium chloride (NaCl) is a neutral salt and does not affect the pH significantly. Therefore, to produce a basic solution suitable for turning phenolphthalein pink, we need a source of hydroxide ions (OH⁻).

The correct answer here is actually not listed in the options, as neither HCl nor NaCl produces a basic solution. However, if considering a hydrochloric solution that reacts with a base subsequently, HCl would lead to a situation where the outcome could be analyzed, but by itself, it does not fit this question context.

Thus, the correct answer to the question regarding which solution turns phenolphthalein pink would typically be one containing a base like sodium hydroxide (NaOH). However, strictly speaking based on the given choices, we would select the closest, which is: (A) HCl.