75.0 mL of 0.100 M NaOH is added to 150. mL of 0.100 M acetic acid, and water is added to give a final volume of 1 L. Find pH

I don't know if it is possible, but I have to make a solution of acetic acid with a pH of 4 and a volume of 250 mL. I have 500 mL of acetic acid 10% and I need to add a certain amount of this acetic acid to the water to have this pH. I was wondering what are the quantities of water and acetic acid I need to "mix" together.  Thank you !

2. In the second titration, the molar mass of an unknown monoprotic acid is calculated.  If 0.100 grams of unknown solid are dissolved in water and titrated with 4.68 mL of the NaOH, what is the molar mass of the solid? HINTS: Molar mass is grams / moles. We have grams from the weighed mass, we can calculate moles of acid from the titration. Monoprotic means that it produces 1 H+ per molecule. This means that our moles of NaOH added and moles of acid are the same. You will need to use your concentration of NaOH from the previous question Which is 0.1186

If a fifth solution (solution E) is made by mixing 10mL of soln C and 10mL of soln D, how will adding 10 mL of water effect the pH