16. Calculation of pH from Molar Concentrations: What is the pH of a solution co

Question

16. Calculation of pH from Molar Concentrations: What is the pH of a solution containing 0.12 mol/L of NH 4 Cl and 0.03 mol/L of NaOH (p K a of NH 1 4 /NH3 is 9.25)? 16. Calculation of pH from Molar Concentrations: What is the pH of a solution containing 0.12 mol/L of NH 4 Cl and 0.03 mol/L of NaOH (p K a of NH 1 4 /NH3 is 9.25)? 16. Calculation of pH from Molar Concentrations: What is the pH of a solution containing 0.12 mol/L of NH 4 Cl and 0.03 mol/L of NaOH (p K a of NH 1 4 /NH3 is 9.25)? 16. Calculation of pH from Molar Concentrations: What is the pH of a solution containing 0.12 mol/L of NH 4 Cl and 0.03 mol/L of NaOH (p K a of NH 1 4 /NH3 is 9.25)?

Explanation / Answer

(NH4)+ reacts with all (OH)- to form NH3 and H2O ( Water )

Concentration of Remaining (NH4)+ = 0.12 - 0.03 = 0.09 mol / L
Concentration of Generated NH3 = 0.03 mol / L


The resulting solution is considered as " NH4+ / NH3 Buffer System " { (NH4)+ is acid ; NH3 is Base ( " Salt " ) }

For a Buffer System :

pH = pKa + Log [ Acid ] / [ Salt ]
= 9.25 + Log [ (NH4)+ ] / [ NH3 ]
= 9.25 + Log [ 0.09 ] / [ 0.03 ]
= 9.25 + Log 3
= 9.25 + 0.4771
= 9.7271

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.