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

In the dissociation of NH4OH,
NH4OH (aq)NH+4 (aq)+OH (aq)
If NH4Cl is added to it, how will the pH for the NH4OH solution change?

A
pH remains the same.
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
pH increases.
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
pH decreases.
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
pH may increase or decrease depending on the concentration of NH4Cl added.
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is C pH decreases.
The dissociation reaction for the weak base , NH4OH is :NH4OH (aq)NH+4 (aq)+OH (aq)
Now, Ammonium chloride is added to the solution. It is a strong electrolyte, which ionizes almost completely as follows: NH4Cl (aq)NH+4 (aq)+Cl (aq)
So with addition of NH4Cl the concentration of NH+4 is increased. Due to the common ion effect, the equilibrium shifts towards backward direction i.e the dissociation of NH4OH is reduced .
Consequently the concentration of OH ions is decreased. As a result the basic character of the medium decreases or acid character increases.
If acid character increases the pH of the medium will decrease.

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
Join BYJU'S Learning Program
CrossIcon