Question

19. Describe how to prepare a buffer solution from NaH2PO4 and Na2HPO4 to have a pH of 7.5.

please write all steps and calculations neatly to help with my understanding. when calculating the ratio please explain how to do so

here's how they solve it but I don't understand the ratio portion

Answer 1

Preparaton butte solution NaM2 Po4 Na24Po4 woeakauid mate baoe StHd H2 Po4 bKa=.21 onjyat base Wea K aui buter Aoluton Con be Calulated uain Hendersm Haad elba ch -euation conjae 60e b4bKa +lo Aeak acid b bRa t loj CNazPo4 Cha po4 7S -1.2 CNa, Po 4) CNGHPO4

0-2= lo CNa,H Po4) CAla H Po4 Taking antig dnti lejo-4)Na, Po4) TNqu, Po4 1- an o 21 m Cat ulatorantilo Calculated as 01 =1.95 CN9nPoa Conjyate 6en ] CNaPO4 weak Now reipor Cali it CNy Poa CNo, HPO4 O-5 Na 4PO4 Na47 Poa weak aud 01511 conjyate base that means Na4, Po4 added |mol Na, uPo OSImol Jmol molNa 4PO4 moi x molr mam j Na, n Pog mang Nou Po4 = 141-969Amu m molNoPo4 0slmel Mam Nan Po q = molar may mol x 61- Answu 0 S1 0961 x 120 j