Question

1. An aqueous solution contains 0.154 M ascorbic acid (H2C6H6O6) and 0.196 M hydrobromic acid. Calculate the ascorbate (C6H6O62-) ion concentration in this solution.

Can you explain how to do this please? thank you.

Also if you can is number 2 missing information or am I supposed to find the ka values?

2. Calculate the concentration of HCO3- in an aqueous solution of 0.0701 M carbonic acid, H2CO3 (aq)?

Answer 1

You can use a short cut on #1 even though the ionization I write below is not quite right. But the equation doesn't know that. :-)
H2A is ascorbic acid
H2A ==> 2H^+ + A^2-
k1k2 = (H^+)^2(A^2-)/(H2A)
Look up k1 and k2, substitute the other numbers and solve for A^2-

#2.
............H2CO3 ==> H^+ + HCO3^-
initial.....0.0701....0.......0
change.......-x.......x.......x.
equil....0.0701-x......x......x

k1 = (H^+)(HCO3^-)/(H2CO3)
Substitute the numbers into k1 and solve for x = HCO3^-. You may need to user the quadratic; i.e., x MAY not be neglected with 0.0701-x. Work it out to see.