    Question

# Given an aqueous solution of 0.034 M carbonic acid, the ionization constants for carbonic acid are K1=4.2×10−7 and K2=4.8×10−11 Select the correct statement from the following:

A
The concentration of CO23 is 0.034 M.
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
The concentration of CO23 is greater than that of HCO3.
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
The concentration of H+ and HCO3 are approximately equal.
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
The concentration of H+ is double that of CO23.
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

## The correct option is C The concentration of H+ and HCO−3 are approximately equal. we can also express dissociation of H2CO3 simpler way as: Step 1 : H2CO3(aq)⇌H+(aq)+HCO−3(aq) at t=0 C 0 0 at t=teq C(1−x) x+y x−y Step 2 : HCO−3(aq)⇌H+(aq)+CO2−3(aq) at t=teq (x−y) x+y yx=[H+] and [HCO−3] and y=[CO2−3] In many cases with Ka1>>Ka2, x>>y ∴x−y≈x and x+y≈x Note:- If C>>x so C−x≈C then C(1−α1)≈C Ka1≈(x)(x)(C−x) where C−x=[H2CO3] and x=[H+] and [HCO−3] Ka2≈(y)(x)(x)≈y Therefore as , [H+]=x+y≈x=[HCO−3]. So , Option c is correct.  Suggest Corrections  1      Similar questions  Related Videos   Degree of Dissociation
CHEMISTRY
Watch in App  Explore more