Presentation is loading. Please wait.

Presentation is loading. Please wait.

Lecture 152/25/04. Quiz 5  Given a 0.25 M solution of NH 3, calculate the pH and the equilibrium concentrations of NH 3, NH 4 +, and OH -. K b = 1.8.

Similar presentations


Presentation on theme: "Lecture 152/25/04. Quiz 5  Given a 0.25 M solution of NH 3, calculate the pH and the equilibrium concentrations of NH 3, NH 4 +, and OH -. K b = 1.8."— Presentation transcript:

1 Lecture 152/25/04

2 Quiz 5  Given a 0.25 M solution of NH 3, calculate the pH and the equilibrium concentrations of NH 3, NH 4 +, and OH -. K b = 1.8 x 10 -5 Equations: K w = K a K b = [H 3 O + ][OH - ]

3 Binary Acids  Within group: HA bond strength decreases (acid becomes stronger) as A increases with size Acid strength: HF < HCl < HBr < HI  Across Row: Stronger acid (more polar - weaker bond) as you move left to right Acid strength: H 2 O < HF Molecular structure and acid strength

4 H-O-Z- Acid strength increases with increases electronegativity HOClHOBrHOI KaKa 3.5 x 10 -8 2.5 x 10 -9 2.3 x 10 -11 electronegativityCl (3.0)Br (2.8)I (2.5) Oxoacids with different central atoms

5 Acid strength increases as the number of O atoms attached to Z increases HOClHClO 2 HClO 3 HClO 4 KaKa 3.5 x 10 -8 1.1 x 10 -2 ~ 10 3 ~ 10 8 HNO 2 vs. HNO 3 H 2 SO 3 vs. H 2 SO 4 Molecular structure and acid strength Oxoacids with the same central atom

6 Acid strength related to R The more electronegative R, the stronger the acid C 5 H 11 -COOHCH 3 -COOHCH 2 Cl-COOHCCl 3 -COOH KaKa 1.4 x 10 -5 1.8 x 10 -5 1.4 x 10 -3 3 x 10 -1 hexanoic acidAcetic acid Chloroacetic acid trichloroacetic acid Carboxylic Acids (R-COOH)

7 Assign pH: (≤ 2, 2-6, 6-8, 8-12, ≥ 12) No calculators 0.1 M solutions  HNO 2  NH 4 Cl  NaF  Mg(CH 3 COO - ) 2  BaO  KHSO 4  NaHCO 3  BaCl 2

8 Put in order high pH to low (0.1 M solutions) KNO 3 Na 2 SO 4 CaO HBr C 6 H 5 COOH NaH

9 Common NameFormulaConstantpKa arsenic acidH 3 AsO 4 K 1 = 5.65 x 10 -3 2.248 H 2 AsO 4 - K 2 = 1.75 x 10 -7 6.757 HAsO 4 2- K 3 = 2.54 x 10 -12 11.596 carbonic acid H 2 CO 3 K 1 = 4.35 x 10 -7 6.361 HCO 3 - K 2 = 4.69 x 10 -11 10.329 chromic acid H 2 CrO 4 K 1 = 3.55-0.550 HCrO 4 - K 2 = 3.36 x 10 -7 6.473 hydrogen sulfideH2SH2SK 1 = 1.02 x 10 -7 6.992 HS - K 2 = 1.22 x 10 -13 12.915 phosphoric acidH 3 PO 4 K 1 = 7.11 x 10 -3 2.148 H 2 PO 4 - K 2 = 6.23 x 10 -8 7.206 HPO 4 2- K 3 = 4.55 x 10 -13 12.342 sulfuric acidH 2 SO 4 K 1 > 1Negative HSO4-HSO4- K 2 = 1.01 x 10 -2 1.994 sulfurous acidH 2 SO 3 K 1 = 1.71 x 10 -2 1.766 HSO 3 - K 2 = 5.98 x 10 -8 7.223

10 Acid–Base Properties of Salt Solution 1. Strong acid + strong base 2. Weak acid + strong base 3. Strong acid + weak base 4. Weak acid + weak base


Download ppt "Lecture 152/25/04. Quiz 5  Given a 0.25 M solution of NH 3, calculate the pH and the equilibrium concentrations of NH 3, NH 4 +, and OH -. K b = 1.8."

Similar presentations


Ads by Google