Question

Solve this last pH question on the page as well as fill in the boxes for me given this information

Given :

SHOW ALL WORK: Calculations for Ammonia Buffer Solution a Moles of NH,CI in 250.0 mL ammonia buffer 3.491 ncid Molarity of NH.Cl in the ammonia buffer ? 32716 SSL Moles of NHs in 250.0 mL ammonia buffer 670 .00003 120 6 ? Molarity of NHs in ammonia buffer SHOW ALL WORK! pH Calculations (4 pts. for each blank and table) ?4.709 pH of ammonia buffer pH of 50.0 mL ammonia buffer + 1.00 mL of 0.6 M HCI NHs ba H30* NH4 before addition Addition after addition 68

Answer 1

Moles of NH_4Cl in 50 mL ammonia buffer = 0.05 L times 0.1308 M = 6.54 times 10^-3 mol Mol. Of NH_3 in 50 mL ammonia buffer = 0.05L times 0.1206 M = 6.03 times 10^-3 M Mol of H^+ in 1 mL of 0.6 M HCL = 0.001L times 0.6 M = 6 times 10^-4 mol So, mol of NH_4Cl after addition of HCl = (6.54 times 10^-3 + 6 times 10^-4) = 7.14 times 10^-3 mol mol of NH_3 after addition of HCl = (6.03 times 10^-3 - 6 times 10^-4) times 100) = 5.43 times 10^-3 so, table will be like: - Now, molarity of NH_3 = 5.43 times 10^-3 mol /0.051 L = 0.106 M Molarity of NH_4Cl = 7.14 times 10^-3 mol /0.051 L = 0.14 M So, pH = pK_a + log [NH_3] /[NH_4^+] pH = 9.25 + log 0.106 M/0.14 M