Question

Hydrogen and chlorine gas are placed in a 10.0 L container and allowed to react. The initial density of the mixture is 5.01 x10^-3 gm/ml. The vessel is at 300K and the initial pressure is 6.52 atm. After the reaction is complete , the pressure is 6.52 atm. The gas is bubbled into 1.00 liter of deionized water. In another part of the universe, a grey haired chemistry instructor prepares an acetic acid/ acetate buffer. The buffer was prepared by adding acetic acid and sodium acetate to 2.50 L of deionized water. Now, as universes collide, our hero adds 107 ml of the HCl solution to 405 ml of the buffer. The pH is measured and is 4.35 after the HCl addition. A drop of phenolphthalein is added and the solution is titrated to equivalence with 657 ml of 0.920 M NaOH. Calculate the original molarities of the weak acid and conjugate base in the 2.50 L solution?

Answer 1

i had to make an assumption that the gases mixture was an idea mixture.

and the pKa of buffer = 4.74