Topic: What is the [H3O+] for a solution labeled “0.10 M H3PO3(aq)” if pKa1 = 2.00 and (Read 2590 times)

Tunechi · « **on:** February 21, 2013, 06:31:57 PM »

Q11. What is the [H3O+] for a solution labeled “0.10 M H3PO3(aq)” if pKa1 = 2.00 and pKa2 = 6.59?
A. 0.027 M
B. 0.054 M
C. 0.20 M
D. 0.015 M
E. 0.15 M

ok so i made an ice table and used the quadratic equation, subbed in the ka value for pka1 (10^-pka1) which is 0.01 and i ended up with 0.027. But i haven't used the pka2 value at all. do i need to? why is it provided? thanks

Borek · « **Reply #1 on:** February 22, 2013, 04:14:16 AM »

In most cases when the difference between consecutive values of pKa is larger than 3, you can ignore the second dissociation step.

Topic: What is the [H3O+] for a solution labeled “0.10 M H3PO3(aq)” if pKa1 = 2.00 and (Read 2590 times)

Tunechi

What is the [H3O+] for a solution labeled “0.10 M H3PO3(aq)” if pKa1 = 2.00 and

Borek

Re: What is the [H3O+] for a solution labeled “0.10 M H3PO3(aq)” if pKa1 = 2.00 and

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