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Question: Can you pleases help plot pKa1 pKa2 midpoints equi...

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can you pleases help plot

pKb1

pKb2

midpoints

equivelnece point 1

equivelnece point 1

and show calculations for them? thank you

pendix B2: 0.00 Appendix B1: 2.00 Titration curve for pH vs volume of HCI 8.00 10.00 4.00 6.00 volume of 0.2568 HCl added (in mL) Part 2 Titration of salt of a diprotic acid. Volume of HCI Volume of Measured burette reading HCI added (mL) Reading (mL) pH 11.11 0.40 0.00 10,84 1.21 0.81 2.01 1.61 10.59 241 10.36 2.81 10.19 3,51 998 4.30 3.90 5.22 9.54 5.90 5.50 6.61 6.21 8.68 73 8.20 2.80 705 880 840 9.20 6.57 10.90 10.50 12.60 12.20 6.16 5.73 13,32 13.72 5.25 14,22 13.82 1440 1400 4,84 3.64 14,25 14.65 3.12 15.05 2.83 14.65 15.40 15.00 2.64 12.00 14.00 16.00

Explanation / Answer

First, estimate the toal volume required to neutralize this diprotic base

Vtotal = 14 mL

then

first protonation = 14/2 = 7 mL

which means

half equivalnece point (1st proton) = 7/2 = 3.5 mL

pH at V = 3.5 mL,

pH = 10.19

pOH = pKb

pOH = 14-10.19= 3.81

pKb1 = 3.81

NOW

second half point:

7+3.5 = 10.5 mL

pH at V = 10.5 approx (6.82+6.57)/2 = 6.69

pOH = 14-6.69 = 7.31

pKb2 = 7.31

Now that we calculated all of them:

pKb1 --> 3.81 at V = 3 mL

pKb2 --> 7.31 at V = 10.5 mL

midpoints --> V = 3 mL; V = 10.5 mL

equivelnece point 1 --> 7 mL

equivelnece point 2 ---> 14 mL

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