An experiment I am planning requires me to prepare an alkaline buffer solution, and I found some sources that said one of 0.1 mol NaHCO3 and 0.1 mol Na2CO3 dissolved in 0.5dm3 distilled water would give a pH value of 9.7. I am not sure how I should find the equilibrium equation for this, as I am not very familiar with such buffers with two salts, as opposed to only one. Thank you in advance for any advice!