Calculate the pH of a solution that has [H₃O⁺] = 1.0 × 10^-6 M. A)pH = 1.00 B)pH = 7.00 C)pH = 6.00 D)pH = 8.00 E)pH = 14.00

Question

Quizplus · Accepted Answer

This question involves the calculation of the pH of a solution given the concentration of an acid. However, we cannot determine which acid is present in the solution as the given formula [HS1U1B13S1U1B0OS1U1P1+S1S1P0] is not recognizable. Therefore, we cannot use the standard Ka values to calculate the pH. As a result, we can assume that the acid is weak and use the approximation that [H+] = [HA]. We can then set up an ICE table to calculate the pH:
                [HS1U1B13S1U1B0OS1U1P1+S1S1P0]  ⇌  H+ + S1U1B13S1U1B0OS1U1P1-

I:                      1.00 ×10^-6 M              0M              0M
C:                     -x                            +x              +x
E:                 1.00 × 10^-6 - x           x              x
Since [H+] = x, we can plug this value into the equation for Ka and solve for x:
Ka = [H+] [S1U1B13S1U1B0OS1U1P1-] /[HS1U1B13S1U1B0OS1U1P1+S1S1P0] 
10^-14 / Ka = [HS1U1B13S1U1B0OS1U1P1+S1S1P0] /[H+] - [S1U1B13S1U1B0OS1U1P1-]
10^-14 / Ka = (1.00 ×10^-6) / x
x = sqrt (Ka × [HS1U1B13S1U1B0OS1U1P1+S1S1P0]) 
As we do not know the value of Ka, we cannot calculate x exactly, but we can make the assumption that the acid is weak, which means Ka < 1 × 10^-6. Therefore, we can simplify the calculation as follows:
x = sqrt (Ka × [HS1U1B13S1U1B0OS1U1P1+S1S1P0]) 
  = sqrt [(1 × 10^-6) × (1 × 10^-6)]
  = 1 × 10^-6
Hence, pH = -log[H+] = -log(1 × 10^-6) = 6. Answer: C

Calculate the PH of a Solution That Has [H3O+] =

Calculate the PH of a Solution That Has [H₃O⁺] =