Question

Question 7 0.77 pts Title q7a7 Which of the following pairs of species, when mixed together in water in proper ratios, would provide a buffer solution? Think each pair through very carefully in terms what species will form when they dissolve in water, and how they can then (potentially) react with water Refer to the table of strong acids/bases on the exam information sheet if you don't have them memorized yet. () KOH and NH4CI (ii)HCI and NH4CI (liI) NH3 and HC (iv) NH3 and NH4CI (v) NH3 and NaOH (iv) only (i), (ii), and (iv) only (iii). (iv), and (v) only (), (iiI) and (iv) only all of these will form buffer solutions 0.77 pts Question 8 Title q8a15 A commonly used biological buffer is MOPS, a weak acid (let's call it HA) with a pKa of 7.20. You have a 1.00 liter solution contain ing 0. 15 M HA and 0.15 MA. By how much will the pH change upon addition of 0.02 moles of HCl? Assume there is no volume change upon adding the HCI. Note that the change in pH is ApH, where ApH pHfinal- pHinitial -0.89 -0.12 0.77 +0,89 +0.12 Question 9 0.77 pts Title q9a8 You mix solutions of AgNO3 and NaCl and observe the formation of a precipitate of AgCI (s). The concentrations of dissolved Ag x 104 M (Ag) and 3.33 x 10 M (CI). What is Ksp for AgCI? and Cl in the solution are found to be 5.40 1074. 4 5.40 x 10 6.17x 104 3.33 x 107 10 1.80 x 10 1.62x 103

Answer 1

Answer :-

These questions are solved by using simple concept of ionic equilibrium reaction and expression of Ksp and buffer concept.

The answer is given in the image,

Andauer 0),(ii and endy cauye bferaare foraned by weakkae amdl its salt uitb streng acid CHA oSM CAJ0.15M Uole 1.oL pka 7.20 Inital pH= pka+ Jo A CHAJ 720+ Je o15 STo pH 420 Moles of HCLadded 0.02 mol. Nat mah e HA = o-15+0-02 = o-17mol,' Net moles a A= o.L5-0-02 =0.13 mol. Final СHR] pH7.20-0-12 &polorot t =nd pH7.08 Phchamge= 7.08-720 = -o-12 o-о.12 солetonшes. kseCAgt (5.40x104)(3-33xo) Кр 1.80x10-1o 1.80xLo 10 crect