wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

For MK3A (potassium salt of a tribasic acid H3A) solution:
(Dissociation constants of acid are ka1ka2&ka3;h<<1)

A
pH=12(pKw+pKa3logc)
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
pH=12(pKw+pKa2+logc)
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
pH=12(pKw+pKa1+logc)
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
pH=12(pKwpKa3logc)
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B pH=12(pKw+pKa3logc)
K3A i.e. A3
A3+H2OHA2+OHK3KwKa3
HA2+H2OH2A+OHK2KwKa2
H2A+H2OH3A+OH.K1KwKa1
Ka1>Ka2>Ka3
K3>K2>K1
[OH] will be most form 1st reaction
A3+H2OHA2+OH
c o o
c(1α) cα cα
cα2(1α)=kwKa3
α is way less than 1
cα2KwKa3
α=KwcKa3
[OH]=cα
=cKwKa3
[H+Kw[OH]=Ka3Kwc
PH=1α(pKw+pKa3logC)

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
pH and pOH
CHEMISTRY
Watch in App
Join BYJU'S Learning Program
CrossIcon