[Edher]

Saludos,

    Acetylsalicylic acid, HC9H704, is the active component in an aspirin. This acid is the cause of the stomach upset some people get when taking aspirin. Two extra-strength aspirin-tablets, each containing 500mg of acetylsalicylic acid, are dissolved in 325 mL of water. What is the pH of this solution?  Ka=3.3x10^-4

HC₉H₇O₄ + H₂O <-->H₃O⁺ + C₉H₇O₄^-


My steps,
- The molar mass of the 1g of aspirin. (0.00555 moles)
- The molarity of aspirin dissolved in water (0.01708 M)
- ICE method.
     x   ² = 3.3x10^-4
   0.01708-x
- Quadratic Formula. (x=0.004429)
- Negative Log of x. (2.65)


The right answer is 11.28.

Where did I go wrong?

Thank You in Advance,
Edher

[Demotivator]

How can ph 11 be right? It's an acid!  

[Edher]

Saludos Demotivator,

       It turns out that it was yet another typo. I checked my notes and indeed my professor had pointed it out.

Thank You,
Edher