Why is NaHCO3 a base?

(I need someone to explain it using the ka values)

H2CO3 HcO3 - + H + ka = 4.3x10^-7

HCO3 - CO3^2 - + H + ka = 5.61x10^-11

if I underestand correctly, the kb for the second equation is greater than the ka. Thus the reaction will not proceed forward, but rather produce more HCO3-. This is a basic tendency. Why is it more powerful than the first reaction?

Question

Chemistry

Molly Walls

27 May, 18:58

Why is NaHCO3 a base?

(I need someone to explain it using the ka values)

H2CO3 HcO3 - + H + ka = 4.3x10^-7

HCO3 - CO3^2 - + H + ka = 5.61x10^-11

if I underestand correctly, the kb for the second equation is greater than the ka. Thus the reaction will not proceed forward, but rather produce more HCO3-. This is a basic tendency. Why is it more powerful than the first reaction?

+3

Answers (1)

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Carson Holland · Answer 1

An aqueous solution of sodium bicarbonate would be having a pH value above 7, whatever its concentration. NaHCO3 is a salt of a weak acid, H2CO3, and a strong base, NaOH. Since carbonic acid is a weak acid, it remains undissociated.