Physics calculation- does anyone understand the solution to this question?

PH Calculation of acid and basis solutions? Help? (:?

• Can anyone help me solve and understand these questions? I just need to check my answers so I can review for my test tomorrow. Your help would be much appreciated! (: 1) What is the pH of a 0.001 M HCl solution using the equation of ionization of HCI in water: HCl + H20 --> H3O+ + Cl- a) 1 b) 3 c) 5 d) 9 e) 11 2) What is the pH of a solution with a molar concentration of H2SO4 of 0.00005M if the ionizaion reaction of sulfuric acid in water is: H2SO4 + H2O --> 2H3O + + PO4 ^2- a) 1 b) 2 c) 3 d) 4 e) 5 3) A sodium hydroxide (NaOH) solution has a concentration of 1.0 x 10 ^ -4 M. 10 ml of the solution are placed in a flask and enough water is added to make 1 L solution. What is the PH of the new solution? a) 4 b) 6 c) 8 d) 10 e) 12 Thank you, i really hope it's not too much to ask.

• Answer:

  We us the log formula located on you calculator = -log( insert M ) = pH 1. -log(0.001) = 3. Therefore your answer is B 2. 2 hydrogens, multiply M x 2 = 0.00005M x 2 = 0.0001. Now we can use the log formula = -log(0.0001) = 4. Your answer is D 3. Firsty notice that OH is present, this means we have to get the base first (pOH) -log(1.0 x 10 ^ -4) = 4pOH pOH + pH always add up to give 14 To find the pH, we simply subtract 14 - 4pOH = 10pH. Your answer is D. And no, it was not too much to ask for.