Posted by MiShell on Tuesday, April 13, 2010 at 6:39pm.
Consider the titration of 29.00 mL of aqueous ammonia with 18.70 mL of 0.1250 M HCl (aq). Kb for NH3 (aq) is 1.8 x 10^-5.
A.) What is the formula of the solute at the equivalence point?
B.) What is the balanced equation for the ionization of the cation of the solute?
C.) What is the molarity of the solute at the equivalence point?
D.) What is the pH at the equivalence point?
- College Chemistry - DrBob222, Tuesday, April 13, 2010 at 8:34pm
You must recognize what is going on in the titration. The equation is
NH3.H2O + HCl ==> NH4Cl + H2O
Obviously NH4Cl is what you have at the equivalence point.
Hydrolyze NH4Cl to determine the pH of th solute.
NH4^+ + H2O ==> H3O^+ + NH3
Set up the ICE chart, and plug all into Ka for the hydrolysis. Ka = (Kw/Kb) =
molarity of solute is moles/L.
Post your work if you get stuck.
- College Chemistry - MiShell, Tuesday, April 13, 2010 at 9:09pm
I understand the ICE chart, but I'm unsure where you get the values to put in the chart?
- College Chemistry - Olereb48, Friday, April 8, 2016 at 3:01pm
This is hydrolysis of 'salt' ions... After titration to equivalence point, only salt remains in solution. Before hydrolysis, only salt ions will be present. Using NH4Cl => NH4+ + Cl- only the NH4+ will under go hydrolysis because theoretically Cl- + HOH => HCL + OH-. However, HCl being a strong acid (electrolyte) prefers to remain 100% ionized. This leaves:
NH4+ + HOH => NH4OH + H+
Ci: [salt] --- 0 0
∆C: -x --- +x +x
Ceq [salt-x]* --- x x
*you can drop 'x' under NH4+
Apply equilibrium row to Ka expression for Hydrolysis of NH4+.
Ka(NH4+) = (Kw/Kb)
=(x)(x)/[NH4+] = x^2/[NH4+]
x = [H+] = ((Kw/Kb)[NH4+])^1/2
pH at equivalence point = -log[H+]
Answer This Question
More Related Questions
- Chemistry - Ammonia has the formula NH3. Household ammonia is a dilute aqueous ...
- Analytical Chemistry - A 22.617 g sample of aqueous waste leaving a fertilizer ...
- Chemistry - A 51.46 mL sample of an ammonia solution is analyzed by titration ...
- chemistry - A 23.596 g sample of aqueous waste leaving a fertilizer manufacturer...
- Chemistry - A 23.596 g sample of aqueous waste leaving a fertilizer manufacturer...
- Chemistry-TITRATION - A titration of 15.0 cm3 of household ammonia, NH3, ...
- CHEMISTRY - Write the formulas for the following substances as they would appear...
- chemistry college - Consider the titration of 30.0 mL sample of 0.050 M NH3 with...
- Chemistry - Concentrated aqueous ammonia contains 1.00 mol NH3 dissolved in 2.44...
- CHEMISTRY - A titration of 15.0 cm3 of household ammonia, NH3, required 38.57 ...