$$pH = -\log[H^+]$$

where [H^+] represents the hydrogen ion concentration in moles per liter (mol/L).

Given [H^+] = 7.0 x 10-2 mol/L, we can calculate the pH:

$$pH = -\log(7.0 \times 10^{-2}) \approx 1.15$$

Therefore, the pH of the solution is approximately 1.15.