PSC 4012 Ionic Phenomena: A study of an environmental problem
PSC 4012: Neutralization & Indicators c(H + )pH = - log c(H + )Solution mol/L1Acid (H + ) mol/L2Acid (H + ) mol/L3Acid (H + ) mol/L4Acid (H + ) mol/L5Acid (H + ) mol/L6Acid (H + ) mol/L7Neutral (H 2 O) mol/L8Basic (OH - ) mol/L9Basic (OH - ) mol/L10Basic (OH - ) mol/L14Basic (OH - )
PSC 4012: Neutralization & Indicators Acids Red and blue litmus paper turn Red Arrhenius: acids release H + when dissolved in Water (aqueous solution) HF (l) + H 2 O H + (aq) + F - (aq) H 2 SO 4 (l) + H 2 O 2H + (aq) + SO 4 2- (aq) HI (l) + H 2 O H + (aq) + I - (aq)
PSC 4012: Neutralization & Indicators Bases Red and blue litmus paper turn Blue Arrhenius: bases release OH - when dissolved in Water (aqueous solution) NaOH (s) + H 2 O Na + (aq) +OH - (aq) Mg(OH) 2 (s) + H 2 O Mg 2+ (aq) + 2OH - (aq) NH 4 OH (l) + H 2 O NH 4 + (aq) + OH - (aq)
PSC 4012: Neutralization & Indicators Salts Made of a metal ion and a non-metal ion Red and blue litmus paper turn do not change colour Neutral (pH = 7) Arrhenius: salts release ions other than H + and OH - when dissolved in Water (aqueous solution) NaCl (s) +H 2 O Na + (aq) + Cl - (aq) CaCl 2 (s) +H 2 O Ca 2+ (aq) + 2Cl - (aq) AgNO 3(s) +H 2 O Ag + (aq) + NO 3 - (aq)
PSC 4012: Neutralization & Indicators Neutralization:
PSC 4012: Neutralization & Indicators Neutralization:
PSC 4012: Neutralization & Indicators Acidic solution (pH = 1) Add NaOH pH increases (1 – 7) Neutral solution (pH = 7) Add NaOH pH increases (7 – 14) Basic solution (pH = 14) Add HCl pH decreases (14 – 7) Neutral solution (pH = 7) Add HCl pH decreases (7 – 1) Acid solution (pH = 1)
PSC 4012: Neutralization & Indicators Practice: Ex. 6.15, p Ex. 6.16, p. 6.35
PSC 4012: Neutralization & Indicators pH Property that distinguishes acidic, basic and neutral solutions Measures the concentration of H + ions in solution Can be determined by indicator, pH paper, pH meter, etc. pH scale: 0 – 14 pH < 7 (Acidic solution: Acids) pH = 7 (Neutral solution: Salts) pH > 7 (Basic solution: Bases)
PSC 4012: Neutralization & Indicators Indicators: What is an indicator?!
PSC 4012: Neutralization & Indicators Indicators:
PSC 4012: Neutralization & Indicators Indicators: What is an indicator?! Substance whose colour changes according to the level of pH of the solution that it is added to
PSC 4012: Neutralization & Indicators Indicators:
PSC 4012: Neutralization & Indicators Indicators: The change of colour occurs in a range of pH (turning point) that is particular for every indicator. Fig 5.8, p Fig 5.9, p. 5.48
PSC 4012: Neutralization & Indicators Practice: Ex & 5.35 p. 5.49