Question

answer

Label the titration curve below with the dominant species of sulfurous acid at each point. HSO_3 SO_3^2- H_2SO_3 & HSO_3 H_2SO_3 HSO_3 & SO_3^2-

Answer 1

NOTE:

initially, we have pure acid, so H2SO3 is present mainly

then, we add some base, H2SO3 reacts (partially) to form HSO3-

then, we add enough base, so there is no H2SO3 left, only HSO3-

then, we add more base, the HSO3- is reacted to form (partially) SO3-2

eventually, at the end, we hav eneough base that only SO3-2 is present since all H+ reacts

14 12 SO32 10 pKa2 7.19 8 SO3 2 6 4-H2SO3 HSO3 2 H2SO3 & HSOa pka1 = 1.85 0 20 40 60 80 100 Volume of NaOH added (mL)