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Titration Graphs. Strong Acid - Strong Base. Investigating the titration between:. 1M HCl and 1M NaOH. Strong Acid - Strong Base. HCl. 10 ml NaOH. Strong Acid - Strong Base. HCl. 10 ml NaOH. Strong Acid - Strong Base. HCl. 10 ml NaOH. Strong Acid - Strong Base. HCl. 10 ml NaOH.
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Strong Acid - Strong Base Investigating the titration between: 1M HCl and 1M NaOH KeMsoft06
Strong Acid - Strong Base HCl 10 ml NaOH KeMsoft06
Strong Acid - Strong Base HCl 10 ml NaOH KeMsoft06
Strong Acid - Strong Base HCl 10 ml NaOH KeMsoft06
Strong Acid - Strong Base HCl 10 ml NaOH KeMsoft06
Equivalence point at pH7 Strong Acid - Strong Base 1NaOH + 1HCl = NaCl + H2O NaOH + HCl = NaCl + H2O 1M 1M 10ml 10ml Solutions mixed in the right proportions according to the equation. KeMsoft06
Strong Acid - Strong Base Running acid into alkali Running alkali into acid KeMsoft06
Strong Acid - Weak Base Investigating the titration between: 1M HCl and 1M NH3(aq) KeMsoft06
Weak base so initial pH value is less than 14 pH starts to fall quickly as acid is added acid alkali Strong Acid - Weak Base 1NH3 + 1HCl = NH4Cl 1M 1M 25ml 25ml pH falls less quickly as buffer soln formed (excess NH3 and NH4Cl present) Soln at equivalence point is slightly acidic because ammonium ion is slightly acidic NH4+ + H2O NH3 + H3O+ KeMsoft06
Excess of acid present – graph same as when adding strong acid to strong alkali Strong Acid - Weak Base After equivalence point the soln contains NH3 and NH4Cl – a buffer soln and so resists large increse in pH so graph flattens out. alkali acid KeMsoft06
Strong Acid - Weak Base Running acid into alkali Running alkali into acid KeMsoft06
Weak Acid - Strong Base Investigating the titration between: 1M CH3COOH and 1M NaOH KeMsoft06
Excess of alkali present – graph same as when adding strong acid to strong alkali acid alkali Weak Acid - Strong Base 1CH3COOH + 1NaOH = CH3COONa 1M 1M 25ml 25ml Soln at equivalence point is slightly alkaline because ethanoate ion is slightly alkaline pH falls less quickly as buffer soln formed (excess CH3COOH and CH3COO- present) CH3COO-+ H2O CH3COOH + OH- KeMsoft06
pH starts to rise quickly as alkali is added alkali acid Weak Acid - Strong Base Excess of alkali present – graph same as when adding strong alkali to strong acid pH rises less quickly as buffer soln formed (excess CH3COOH and CH3COO- present) KeMsoft06
Weak Acid - Strong Base Running acid into alkali Running alkali into acid KeMsoft06
Weak Acid - Weak Base Investigating the titration between: 1M CH3COOH and 1M NH3 KeMsoft06
acid alkali Weak Acid - Weak Base 1CH3COOH + 1NH3 = CH3COO- + 1NH4+ About as weak as each other - KeMsoft06
acid alkali Weak Acid - Weak Base No steep section – small addition of acid causes a large change in pH, so… Very difficult to do a titration between a weak acid and a weak base. KeMsoft06
Weak Acid - Weak Base KeMsoft06
Complicated titration curves Strong Acid - Weak Base Hydrochloric acid and sodium carbonate hydrochloric acid 1 Na2CO3 + HCl NaCl + CO2 + H2O 2 2 Assume both solutions are of the same concentration Reacting ratio is 1:2 Twice the volume of hydrochloric acid required to reach the equivalence point Sodium carbonate KeMsoft06
50 50 Complicated titration curves Na2CO3 + 2HCl 2NaCl + CO2 + H2O weak base, CO32- hydrochloric acid Twice the volume of hydrochloric acid required to reach the equivalence point 50cm3 Sodium carbonate 50 25cm3 KeMsoft06
Complicated titration curves Na2CO3 + 2HCl 2NaCl + CO2 + H2O hydrochloric acid Twice the volume of hydrochloric acid required to reach the equivalence point 50cm3 Sodium carbonate 25cm3 KeMsoft06
Complicated titration curves Na2CO3 + 2HCl 2NaCl + CO2 + H2O NO CO2 observed whilst adding first 25 ml of acid hydrochloric acid A CO2 observed whilst adding next 25 ml of acid Twice the volume of hydrochloric acid required to reach the equivalence point B 50cm3 excess acid Sodium carbonate 25 50 25cm3 KeMsoft06
Complicated titration curves Na2CO3 + 2HCl 2NaCl + CO2 + H2O Na2CO3 + HCl NaCl + NaHCO3 A NaHCO3 + HCl NaCl + CO2 + H2O B KeMsoft06
Complicated titration curves Na2CO3 + 2HCl 2NaCl + CO2 + H2O Na2CO3 + HCl NaCl + NaHCO3 NaHCO3 + HCl NaCl + CO2 + H2O Na2CO3 + 2HCl 2NaCl + CO2 + H2O A B KeMsoft06
Complicated titration curves Weak Acid - Strong Base Ethanedioic acid and sodium hydroxide Sodium hydroxide Assume both solutions are of the same concentration Reacting ratio is 1:2 1 (COOH)2 + NaOH (COONa)2 + H2O 2 Twice the volume of sodium hydroxide required to reach the equivalence point. Two hydrogen ions can be formed per molecule of the acid. It is a… ethanedioic acid DIPROTIC ACID KeMsoft06
50 50 Complicated titration curves 1 (COOH)2 + NaOH (COONa)2 + H2O 2 sodium hydroxide Twice the volume of sodium hydroxide required to reach the equivalence point 50cm3 fairly strong acid ethanedioic acid 50 25cm3 KeMsoft06
sodium hydroxide Twice the volume of sodium hydroxide required to reach the equivalence point 50cm3 ethanedioic acid 25cm3 Volume of alkali added (cm3) Complicated titration curves (COOH)2 + 2NaOH (COONa)2 + H2O reaction is in TWO stages one of the hydrogens is easier to remove than the other KeMsoft06
Choosing an Indicator 3.7 9.3 KeMsoft06
Strong Acid - Strong Base KeMsoft06
Strong Acid - Weak Base KeMsoft06
Weak Acid - Strong Base KeMsoft06
Weak Acid – Weak Base KeMsoft06
Acid - Carbonate KeMsoft06