The pH of this solution : 0.699
Further explanation
pH is the degree of acidity of a solution that depends on the concentration of H⁺ ions. The greater the value the more acidic the solution and the smaller the pH.
pH = - log [H⁺]
So that the two quantities between pH and [H⁺] are inversely proportional because they are associated with negative values.
A solution whose value is different by n has a difference in the concentration of H⁺ ion of 10ⁿ.
A solution has a [H+] of 0.20 M, so [H⁺]=0.2
![\tt pH=-log[H^+]\\\\pH=-log[0.2]\\\\pH=1-log~2\\\\pH=0.699](https://img.qammunity.org/2021/formulas/chemistry/college/uc9josfn54kbpgsi0cf1ecpgo59ll97uul.png)