1. Acid – Base Titration

2. (titration is a neutralization reaction)
30/09/99
Titration: the progressive addition of a base to an acid or an acid to a base.
It is a volumetric method of analysis used to find the concentration of an acid or base. NaOH + HCl  H2O + NaCl
(titration is a neutralization reaction)
Endpoint: the point when the indicator colour changes (usually at the end of the titration)
Equivalence point: The point when the number of equivalents mixed together are the same (in acid-base titrations equivalents refer to the number of moles of H+ and OH–)

3. Titration Formula #H x MA x VA = #OH x MB x VB
30/09/99
#H x MA x VA = #OH x MB x VB
MA = concentration of acid
MB= concentration of base
VA = volume of acid
VB = volume of base
#H = the number of H’s in the acid
#OH = the number of OH’s in the base

4. Titration problems
What volume of 0.10 mol/L NaOH is needed to neutralize 25.0 mL of 0.15 mol/L H3PO4?
25.0 mL of HCl(aq) was neutralized by 40.0 mL of 0.10 mol/L Ca(OH)2 solution. What was the concentration of HCl?
A truck carrying sulfuric acid is in an accident. A laboratory analyzes a sample of the spilled acid and finds that 20 mL of acid is neutral-ized by 60 mL of 4.0 mol/L NaOH solution. What is the concentration of the acid?

5. Titration problems 1. (3)(0.15 M)(25 mL) = (1)(0.10 M)(VB)
VB= (3)(0.15 M)(25 mL) / (1)(0.10 M) = mL
2. (1)(MA)(25 mL) = (2)(0.10 M)(40 mL)
MA= (2)(0.10 M)(40 mL) / (1)( 25mL) = 0.32 M
3. Sulfuric acid = H2SO4
(2)(MA)(20 mL) = (1)(4.0 mol/L)(60 mL)
MA = (1)(4.0 M)(60 mL) / (2)(20 mL) = 6.0 M