Analyze the pH of each salt solution: NaC2H3O2, NH4I, KHCrO4. For KHCrO4 Ka1=1.5
ID: 1004799 • Letter: A
Question
Analyze the pH of each salt solution: NaC2H3O2, NH4I, KHCrO4.
For KHCrO4 Ka1=1.5X10^-4, Ka2=1.0X10^-9
How do I do this without the Ka values for NaC2H3O2 and NH4I?
Example:
NaHCO3 Na+ HCO3 GP1A cation cónj. base of weak diprotic acid has ionizable H neutral 14 K, 1.0×10-14 5.6x10".' K, = an a 4.3x107 = 2.4x10-5 > K basic basic NH&NO2; 2nase of NH4 NO2 conj. acid of weak base conj. base of weak acid acidic basic K, 1.0×10-14 1.8x10-5 ~ 1.0×10-14 4.0x10 14 = 5.6×10-10 = 2.5×10-11 > acidicExplanation / Answer
Consider the given salt is a combination of an acid and base from which it has prepared.
For example: NaC2H3O2 : it is prepared by NaOH + C2H3O2H in which NaOH is a strong base and C2H3O2H (organic acid) is a weak base. So the pH must be greater than 7
In NH4I : The constituent compounds are NH4OH and HI in which NH4OH is a weak base and HI is a strong acid. Hence pH < 7 when salt is dissoved in water.