Strong acids All (100%) of the H ionize to H+ HCL, H 2 SO 4 , HNO 3 are all strong acids
Strong acids
All (100%) of the H ionize to H+
HCL, H2SO4, HNO3 are all strong acids
Strong Bases
All (100%) of the OH ionize to (OH)-
NaOH and KOH are strong bases
WEAK acids and bases
Not all the hydrogen ions or hydroxide ions come off (ionize) in solution
Carbonic acid and Phosphoric acids are weak
Acid Base Reactions
Acids + Metals
In lab we did an experiment with Zinc and acid:
Zn(s) + HCl (aq) H2(g) + ZnCl2 (aq)
Is this equation balanced? Balance it!What type of reaction is it?If we used copper instead of zinc, what would
happen? (hint: look at Table J)
Neutralization Reactions
Neutralization Reactions
Acid + Base water + a salt
This is true for any acid and base
Because water (pH = 7= neutral) is produced, the acid and the base are neutralized
Write Neutralization Reactions for…
Nitric acid + potassium hydroxide
Sulfuric acid + calcium hydroxide
Magnesium hydroxide and hydrochloric acid
Titration Equation
Remember: Molarity (M) = Moles/Liter
So…. moles = molarity x Liters
Titration Equation
In a neutralization reaction……
the number of moles of acid must be equal to the number of moles of base
(or the end result will not be neutral! )
Titration Equation
Therefore, in a neutralization reaction….
Moles of Acid = Moles of Base or Moles (A) = Moles (B)
Titration Equation
Since we know that Moles = molarity x Liter,We can substitute in for Moles
Moles of Acid = Moles of BaseMolarity(of acid) x liters(of acid) = Molarity(of base) x Liters
(of base)
Titration Equation
We simplify this equation: (see Table T)
Ma x Va = Mb x Vb
Where Ma = molarity of acid Va = volume of acid (in liters) Mb = molarity of base Vb = volume of base (in liters)
Ma x Va = Mb x Vb
What is the concentration of HCl if 50 ml of a 0.25M KOH are needed to neutralize 20 ml of HCL solution?
Ma = ?Va = 20 mlMb = .25MVb = 50 ml
Ma x .02L = .25M x .05L
Ma x Va = Mb x Vb
What is the concentration of HCl if 50 ml of a 0.25M KOH are needed to neutralize 20 ml of HCL solution?
Ma x .02L = .25M x .05L
Ma = .25M x .05L .02L
Ma = .625M
Titration
is used to very accuratelymeasure the volumesof acids and basesduring a neutralizationreaction
Phenolphthalein indicator is clear in acids, pink in bases
Neutralization is reachedwhen the clear solution turns a pale pink
If solution turns a dark pink, too muchbase has been added and the solution is now basic, not neutral
pH
pH
• pH = 7 Neutral (pure water)
• pH 0-6 Acidic
• pH 8-14 Basic
Indicators: Table M
• Change colors in the presence of acids or bases
• Phenolphthalein = clear in acids, pink in bases
• Litmus = red acid Blue Base