A 100.0-mL buffer solution is 0.175 M in HClO and 0.150 M in NaClO. a. What is the initial pH of this solution?

Video transcript

Hello. In this problem, we are told that 0.125 Mueller hydro sonic acid and 0.140 Mueller sodium cyanide are mixed to produce 125 mL of buffer solution were asked to determine the initial ph of the solution were given the acid dissociation constant for hydro sonic acid. So hydro sonic acid is a weak acid will undergo hydraulic sis. So we'll donate a proton to water. We will form cyanide and had you any minds. Sinai then is the conjugate base of our weak acid hydro sonic acid. So they differ by a proton. When we have these together in solution we form a buffer and the cyanide will come from the sodium cyanide. So given that we have a buffer solution, we can make use of the Henderson has a bag equation which tells us that that the ph is equal to the peak A plus log of the concentration of our conjugate base to that of our acid. And so are PK is the negative log of R. K. A. Which for hydro sonic acid is 4.90 Times 10 to the -10. And then we have the log of the concentration of cyanide which is equal to that of sodium cyanide Divided by the concentration of our acid which is 0.125 Mueller. So the ph then works out to 9.359. His PhD and corresponds to answer B. Thanks for watching. Hope this helped