Question

Prelaboratory Assignment 12, Acids and Bases. Name What is the definition of an Brønsted-Low hat is the definition of an Brønsted-Lowry acid? What is the pH range of an acidic solution What is the definition of a Bransted-Lowry base? What is the pH range of a basic solution Calculate the pH of the following solutions: a) [H] = 3.75 x 10M solution b) [H] = 2.5 M 4) Calculate the (H') ion concentration for the following solutions: Calculate the ruli a) pH = 8.5 b) (OH) = 2.5x10* M. 5) If a solution has a pOH of 8.54, what is the pH, (OH') and (H'? 6) Determine the concentration of H' in a pH 6, 7 and 8 solution. How are these concentrations related to one another? a) What happened to the concentration when the pH was increased? 111

Answer 1

According to Bronsted-Lowry acid theory

1. Proton (H+) donor is acid and the pH range of acidic solution is 0 to 7

2. Proton (H+) acceptor is base and the pH range of basic solution is 7 to 14

3. pH of a solution is given by pH = -log(H+)

     a). [H+] = 3.75*10^-6 M; pH = -log(3.75*10^-6) = 5.43

     b). [H+] = 2.5 M; pH = -log(2.5) = -0.397

4. pH of a solution is given by pH = -log(H+) =====> [H+] = 10^-PH

   a). pH = 8.5; pH = -log(H+) = 8.5 =====> [H+] = 3.16*10^-9 M

   b). For any neutral solution, [H+] [OH-] = 1*10^-14

                                  [H+] = 1*10^-14/[OH-] = 1*10^-14/(2.5*10^-4)
                      
                          [H+] = 4.0*10^-11 M

5. For For any neutral solution, pH + pOH = 14

                          pOH = 8.54 ====> pH = 14-8.54 = 5.46

      pOH = -log(OH-) = 8.54 =====> [OH-] = 2.88*10^-9 M

      pH = -log(H+) = 5.46 =====> [H+] = 3.46*10^-6 M

6. pH = -log(H+) = 6 =====> [H+] = 10^-6 M

    pH = -log(H+) = 7 =====> [H+] = 10^-7 M

    pH = -log(H+) = 8 =====> [H+] = 10^-8 M

On observing the concentration, concentration of the H+ solution decreases by 10 units.

for every ten fold dilution, pH of the solution increases by 1 unit.

when pH increases, concentration of H+ ion decreases.