gb nge men by aa to cougn 2om caoe Below is a student's titration curve of the weak acid H2SO3. DoY esolar g bus oli mot. 1. Identify the regions on the graph corresponding to equivalence point #1, equivalence point #2, the approximate pKal and pKa2 points. ( n dul woy Titration of 0.10o M H,SO, ib brte ns t d noniroqo aidi gmidincorob al.1 15 14 13 12 br adi 10 muindilhups o olinW.S 11 10 To sulsv ordi esob wol.E OH lil biao gnone 0. 7. 4. 3. 2oulov uo amo.d 50 10 20 30 40 Vileimad to dondbmfl mL NaOH 2. If the pKal point has a value of 1.85, what is Kal? ni 3. What is the pH at pKal? Hd

Equivalence point: point in titration at which the amount of titrant added is just enough to completely neutralize the analyte solution. At the equivalence point in an acid-base titration, moles of base = moles of acid and the solution only contains salt and water. 

For diprotic acid two equivalence point is possible due to presence of two types of protons 

From the graph we got

1. equivalance point 1 is at 20 ml and pKa1 is 1.85 

equivalance point 2 is at 40 ml and pKa2 is 7.20

2. pka1 = 1.85

We know

pka1 = -logka1 

1.85 = -logKa1,

Ka1= antilog(- 1.85)

= 1.41x 10^-2 

3. pH at pka1 is obtained from the graph that is 4.5