Answer to Question #56947 in General Chemistry for jgore

Question

Captain Kirk of the Starship Enterprise has been told by his superiors that only a chemist can be trusted with the combination of a safe containing the dilithium crystals that power the ship.

The combination is the pH of solution A, described below, followed by the pH of solution C, also described below. (Example: If the pH of solution A were 3.47 and the pH of solution C were 8.15, the combination would be 3-47-8-15.)

Determine the combination of the safe from the information below:

Solution A: is a 0.150 M solution of a weak monoprotic acid HX.

Solution B: is a 0.0500 M solution of NaX, the sodium salt of this acid. It has a pH of 10.55.

Solution C: is made by adding 12.0 mL of 0.2500 M KOH to 50.0 mL of Solution A.

What is the combination to the safe?