pH of an acidic solution should be less than 7 . The reason is that from H2O,[H+]=10−7M which cannot be neglected in comparison to 10−8M. The pH can be calculated as. From acid, [H+]=10−8M From H2O,[H+]=10−7M ∴ Total [H+]=10−8+10−7 =10−8(1+10)=11×10−8 ∴pH=−log[H+]=−log11×10−8 =−[log11+8log10] =−[1.0414−8]=6.9586