CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Calculate the equilibrium constants for the reactions with water of H2PO4,HPO24 and PO34 as base. Comparing the relative values of two equilibrium constants of H2PO4 with water, deduce whether solutions of this ion in water are acidic or bases. Deduce whether solutions of HPO24 are acidic or bases. Given K1,K2 and K3 for H3PO4 are 7.1×103,6.3×108 and 4.5×1013 respectively .

A
1.4×1012,1.6×107,2.2×102,H2PO4 is acidic and HPO24 is basic
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
2.2×1012,1.6×107,1.4×102,H2PO4 is basic and HPO24 is basic
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
2.2×1012,1.6×107,1.4×102,H2PO4 is acidic and HPO24 is basic
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
1.4×1012,1.6×107,2.2×102,H2PO4 is basic and HPO24 is acidic
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B 1.4×1012,1.6×107,2.2×102,H2PO4 is acidic and HPO24 is basic
i. H2PO4+H2OH3PO4+OH
Kh=KwKa=10147.1×103=1.4×1012
ii. HPO24+H2OH2PO4+OH
Kh=KwK2=10146.3×108=1.6×107
iii. PO34+H2OHPO24+OH
Kh=KwK3=10144.5×1013=2.2×102
H2PO4 can react with water to yield HPO24 and H3O with a constant 6.3×108
Its reaction with water to yield H3PO4, OH has a much smaller equilibrium constant, 1.4×1012, and so this ion in water is acidic comparision of the constants for HPO24(4.5×103 as an acid, 1.6×107 as base ) leads to the conclusion that this ion in solution is basic.

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