Question

1 . If a buffer solution is 0.260 M in a weak acid (?a=8.3×10−5)and 0.480 M in its conjugate base, what is the pH?

pH=

2. If a buffer solution is 0.200 M in a weak base (?b=5.0×10−5) and 0.530 M in its conjugate acid, what is the ph

3. Phosphoric acid is a triprotic acid (?a1=6.9×10−3, ?a2=6.2×10−8 , and ?a3=4.8×10−13

To find the pH of a buffer composed of H2PO4 - (aq) ) and HPO4 2− (aq) , which p?a value should be used in the Henderson–Hasselbalch equation?

A .pKa1 = 2.16

B . pKa2 = 7.21

C .p?a3 = 12.32

Calculate the pH of a buffer solution obtained by dissolving 29.0 g of KH2PO4(s) and 40.0 g of Na2HPO4(s) in water and then diluting to 1.00 L.

4. A 0.385 g sample of a diprotic acid is dissolved in water and titrated with 0.260 M NaOH . What is the molar mass of the acid if 34.7 mL of the NaOH solution is required to neutralize the sample? Assume the volume of NaOH corresponds to the second equivalence point.

5. For the titration of 65.0 mL of 0.300 M NH3 with 0.500 M HCl at 25 ∘C, determine the relative pH at each of these points.

before the addition of any HCl.

pH>7

pH<7

pH=7

Determine the relative pH after 39.0 mL HCl has been added.

pH<7

pH=7

pH>7

Determine the relative pH after 59.0 mL HCl has been added.

pH>7

pH=7

pH<7

6.Calculate the pH for each case in the titration of 50.0 mL of 0.230 M HClO(aq)with 0.230 M KOH(aq).. Use the ionization constant for HClO..

What is the pH after addition of 40.0 mL KOH?

7. A volume of 500.0 mL of 0.110 M NaOH is added to 545 mL of 0.200 M weak acid (?a=6.97×10−5). What is the pH of the resulting buffer?

HA(aq)+OH−(aq)⟶H2O(l)+A−(aq)

Answer 1

A- weak acld - HA conjugate base of weak acid - CHAJ= 0.260 M [A-] = 0.480 M Ko of HÀ (weak cocid) = 8.3x10-5 pka : -log ka = -lug 18.3X16-57 = 4.08 Using Henderson Hasselbalch equation & pH = pka - 4.08 & loc log [AT CHAT 0.480 M 0.260M TpH = 4.34 Answer Kindly post different questions Please Rate separately.