i keep getting 1 wrong.. its says the total V is hcland water added together but i did it and its not right. thanks

1. You add Hydrochloric Acid to distilled water. Ifall the HCl dissociates in solution, calculate the pH of the finalsolution given the following data. (assume the liquid volumes areaddative)
Volume of distilled water used 27.81 mL
Volume of HCl added 1.44 mL
Concentration of added HCl 1.848 M

pH of diluted HCl solution ___________________

2. You weigh a sample of a monoprotic unknown acid anddissolve it in 50.00 mL of distilled water. Exactly half of thissolution is titrated with Sodium Hydroxide to the phenolphthaleinend point.
The pH of the other half of the original solution is measured witha pH meter. The \"neutralized\" solution is added to the \"original\"solution and the pH of this combined \"final\" solution is alsomeasured.
The following are the measured values:
Mass of unknown acid 1.8105 g
Volume of NaOH used in titration 13.80 mL
Concentration of the NaOH used 0.2213 M
pH of the original acid solution 2.13
pH of the final acid solution 3.24

      CALCULATE the following
(a) Molecular Weight of Acid used in titration___________________

(b) Molarity of UNKNOWN Acid solution from titration___________________

(c) Ka of UNKNOWN Acid ___________________

(d) Concentration of undissociated Acid from pH measurements___________________

(e) Total concentration of UNKNOWN acid from pH measurements___________________