Question

21.) Tris, (HOCH₂)₃CNH₂ (pK_b = 5.91), a very common buffer for studying biochemical processes, is prepared by a biological chemist using 10.0M NaOH to a pH of 7.79 using 31.52 g of (HOCH₂)₃CNH₃Cl, or TrisH⁺, (MW=157.597g/mol, pKa 8.075).

>>>> Need help with second part of question pls>>>>...Now you dilute the solution from problem 21 to 1.0 L and take half of the buffer (500.0 mL) and add 0.0100 moles solid HCl. What is the new pH?

Answer 1

It is a basic buffer bot = pk + log [salt] bot = pkt Base] 14-7.79 = 5.91 + log 310522 157.597 Base = 6.21 = 5.91 + log 0.2 Bale 0-3 = log oz 2 = 0.2 Base Moles of Base = 0.1 moles 0.01 Base + ke Dol 0.1-0.01 = 0.09 salt 0.2 0.2 +0.01 = 0. 21 =) por = 5.91 + log 0.21 pon = 5.91 + log 2.33 pon = 6.28 pH = 14-poH = 14-6.28 - pH = 7.72