1)calculate the change in ph when 4 ml of .1 m HCl is added to 100 ml of a buffe
ID: 491172 • Letter: 1
Question
1)calculate the change in ph when 4 ml of .1 m HCl is added to 100 ml of a buffer solution that is .1 m in NH3 and .1 m in NH4Cl 2 calculate the change in ph when 4ml of .1 m NaOH is added to the original buffer solution. 1)calculate the change in ph when 4 ml of .1 m HCl is added to 100 ml of a buffer solution that is .1 m in NH3 and .1 m in NH4Cl 2 calculate the change in ph when 4ml of .1 m NaOH is added to the original buffer solution. 1)calculate the change in ph when 4 ml of .1 m HCl is added to 100 ml of a buffer solution that is .1 m in NH3 and .1 m in NH4Cl 2 calculate the change in ph when 4ml of .1 m NaOH is added to the original buffer solution.Explanation / Answer
The buffer solution is 100mL ofNH3 and NH4 Cl buffer
the Pkb of ammonia is 4.74.
For a buffer the pH is calculated using Hendersen equation as
pH = 14- pOH
= 14 -[ pkb + log [conjugate acid]/[base]]
The initial pH of the buffer = 14-[4.74 + log 0.1/0.1]
= 9.26
case 1) 4 mL of 0.1 M HCl is added
NH3 + HCl ------------------> NH4Cl
100 x0.1 0 100x0.1 initial mmol
4x0.1 change
9.6 0 104 after reaction
Thus pH = 14 -[4.74 + log 104/96]
= 9.225
The chang ein pH = 9.26-9.225
= 0.03476
the pH decrease by 0.03476 units
case2
NH4Cl +Na OH -----------------------> NH3 + NaCl + H2O
100 x0.1 0 100x0.1 initial mmol
4x0.1 change
9.6 0 104 after reaction
Thus the pH of the solution
pH = 14 -[4.74 + log 96/104]
= 9.29476
Thus the pH increases by 0.03476 units
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.