How do you prepare 0.5 M phosphate buffer pH 7.0?

To prepare 0.5 M phosphate buffer pH 7.0, dissolve the appropriate amounts of monobasic potassium phosphate and dibasic potassium phosphate in water. Adjust the pH using either dilute HCl or NaOH, while continuously checking with a pH meter until pH 7.0 is reached. Dilute to the desired final volume with water if needed and ensure that the final pH is within the acceptable range.