1 CHM 2046L Assignment 2 unknowns may contain any of these 2

1. CHM 2046L Assignment 2 unknowns may contain any of these: -2 HSO4 S04 (a) whichf the se would have an effect on the pH of a lution of an unknown? What pH is expected (assuming 0.1 M and no other ion having a significant effect on the pH of water) Ion: gives pH Ion: gives pH Ion : gives pH -gives pH = (b) List the two pH-incompatible pairs of ions. \"Incompatible\" means they could not exist together in the same solution, both in appreciable concentration, because they react with each the r . and or and 2. Human blood is clo3ely buffered to 7.4 ± 0.2, in part due to H2COa and HCOa. For H2Coa in blood, use kal 8 10 (a) Calculate the concentration ratio [H2COal/[HCOal for blood (b) How will the pH of arterial bl a compare with that of venous blood? Hicher or lower (circle one) Briefly indicate why (c) What other CA/CB pair also helps to buffer blood? Select the best answer from the A/B handout (or read the list of contents on a bottle of Gatorade). ca= CB=

Solution

1. (a) NaHSO₄ is highly acidic salt because and gives pH 1 at 0.1M! second I would say NH₄Cl made og weak base and strong acid so will give acidic pH of 5.1 at0.1 M

1. (b) think it would be NaCl and KOH

2. (a)from pH find concentrationof H+ ions. the same will be the concentration og HCO₃^-.

simply using the equilibirum equation,

k = {[HCO₃^-] * [H⁺]}/ [H₂CO₃]

8* 10^-7 = (3.98* 10^-8)²/ (x-3.98 *10^-8)

x=18.05 * 10^-8

[H₂CO₃]= x-3.98 *10^-8 = 18.05 * 10^-8-3.98 *10^-8= 14.07 * 10^-8

so ratio of [H₂CO₃]/[HCO₃^-]= 14.07 * 10^-8/3.98 *10^-8 = 3.53

(b) arterial blood has higher pH. venous blood has lower pH because the carbonic acid in blood plasma dissociates into positive and negative ions as H₂CO₃  ->HCO₃^- + H⁺

presence of H⁺ ions increases acidity decreasing pH.

(c) i cannot answer this one.