12.2-12.5.pdf

1 Fully Protonated Acid Names are Derived from the Conjugate Base ŠLori PetrovichSection 12.2 ide ion hydro___ic acid HFF1- fluoride ion hydrofluoric acidmonoprotonate H2SS2- sulfide ion hydrosulfuric aciddiprotonate Fully Protonated Acid Names are Derived from the Conjugate Base ate ion _____ic acid BrO31- bromate ion bromic acidmonoprotonate HBrO3 SO42- sulfate ion sulfuric aciddiprotonate H2SO4 PO43- phosphate ion phosphoric acidtriprotonate H3PO4 Section 12.2 Fully Protonated Acid Names are Derived from the Conjugate Base ite ion _____ous acid BrO21- bromite ion bromous acidmonoprotonate HBrO2 SO32- sulfite ion sulfurous aciddiprotonate H2SO3 PO33- phosphite ion phosphorous acidtriprotonate H3PO3 ŠLori PetrovichSection 12.2 Fully Protonated Acid Names are Derived from the Conjugate Base (don?t forget your prefix for Group VII) ite ion ous acid ClO1- hypochlorite ion hypochlorous acidmonoprotonate HClO Section 12.2 ate ion ic acid ClO41- perchlorate ion perchloric acidmonoprotonate HClO4 A Few Special Acid Names NH3 ammonia ammonium ionmonoprotonate NH41+ CN1- cyanide ion hydrocyanic acidmonoprotonate HCN OH1- hydroxide ion watermonoprotonate H2O H2O water hydronium ionmonoprotonate H3O1+ Section 12.2 Naming Oxoanions Reminder Section 4.2 Groups 4, 5 & 6 Group 7 ClO41- perchlorate ion ClO31- chlorate ion ClO21- chlorite ion ClO1- hypochlorite ion CO32- carbonate ion NO31- nitrate ion NO21- nitrite ion PO43- phosphate ion PO33- phosphite ion SO42- sulfate ion SO32- sulfite ion 2 hydrosulfuric acid H2S sulfide ion S2- H2SO4 sulfuric acidsulfate ion SO42- H2SO3 sulfurous acidsulfite ion SO32- Neutral acids containing S Section 12.2 Name HBrO 1. Hydrobromic acid 2. Hypobromous acid 3. Bromous acid 4. Hydrogenbromide oxide Name HBrO4 1. Hydrogen perbromate 2. Perbromate acid 3. Bromic acid 4. Perbromic acid Name HBr 1. Hydrogen bromide 2. Hypobromous acid 3. Hydrobromic acid 4. Bromic acid Name H2CO3 1. Hydrocarbonic acid 2. Dihydrogen carbonate 3. Carbonous acid 4. Carbonic acid Name HNO2 1. Nitrous acid 2. Nitric acid 3. Hydrogen nitrite 4. Nicholas 3 A simple matter of filling in conjugate base conjugate acid HF + NO21- acid base F1- HNO2 conjugate base (remove an H, make charge lower by 1) + conjugate acid (add an H make charge greater by 1) Section 12.3 Bronsted Acid-Base Reactions conjugates conjugates SO42- + H3O1+ acidbase H2O+ conjugate base (remove an H make charge less by 1) HSO41- conjugate acid (add an H make charge greater by 1) Section 12.3 Bronsted Acid-Base Reactions A simple matter of filling in conjugate base conjugate acid conjugates conjugates The acid-base reaction that occurs when sodium acetate is dissolved in water. acid + H2O OH 1-+ conjugate base (subtract an H1+) HC2H3O 2 conjugate acid (add an H1+) Section 12.3 NaC2H3O2 (s) Na1+(aq) + C2H3O21- (aq) Dissolution Reaction: C2H3O21- base Aicd-Base Reaction: Bronsted Acid-Base Reactions Complete the Acid-Base Reaction S2- + HClO3 1. H2S + ClO31- 2. HS1- + ClO31- 3. H2S + ClO32- 4. HS + ClO32- Complete the Acid-Base Reaction NH41+ + SO32- 1. NH3 + HSO3 2. NH21- + H2SO3 3. NH3 + HSO31- 4. NH3 + H2SO3 A simple matter of filling in conjugate base conjugate acid HCO31- + HPO42- acid base Section 12.4 What? How do I figure out which one is the acid? When we finish with Ka, you?ll know. + conjugate base (subtract an H1+) conjugate Acid (add an H1+) CO32- H2PO41- Bronsted Acid-Base Reactions 4 CH3COO1- + HCNCH3COOH + CN1- Section 12.4 Bronsted Acid-Base Reactions K = [CH3COO 1-][HCN] [CH3COOH][CN1-] If K is >1, we should leave the room. If K is <1, we?re going to be OK. When we finish with Ka, you?ll know. Acids: Donates proton easily ?Strong acid Has smaller amount of ?glue? holding proton on. ?Weak acid ?Holds on? to proton Has larger amount of ?glue? holding proton on. electron density Section 12.5 Predicting Acid & Base Strengths Bases: ?Strong base Has larger amount of ?glue? available with which to ?grab? proton (i.e., electron density to share w/ proton). ?Weak base Has smaller amount of ?glue? available with which to ?grab? proton. Section 12.5 Predicting Acid & Base Strengths A) Which acid is the strongest (i, ii or iii)? B) Which acid is the weakest (i, ii or iii)? i H H Hiiiii Section 12.5 Strongest Weakest Predicting Acid & Base Strengths The weaker the bond the ______er the acidstrong i ii iii Strongest Weakest A) Which base is the strongest? B) Which base is the weakest? Section 12.5 Predicting Acid & Base Strengths Conjugate acid-base pairs Weaker acidH HStronger acid Stronger base Weaker base Section 12.5 Predicting Acid & Base Strengths 5 Which is the strongest acid: a, b, c or d? H F H Cl H H Br I a b c d H-X where X varies within the same family, acid strength depends on the strength of H-X bond Section 12.5 H-F: 565 kJ/mol H-Cl: 432 kJ/mol H-Br: 366 kJ/mol H-I: 299 kJ/mol H-X Bond energy Predicting Acid Strengths (when H is bonded to something other than oxygen) Which is the strongest acid: a, b, c or d? H C HH H H N H H H O H H F a b c d + - + - + - Section 12.5 The more polar the bond the stronger the acid H-CH3 H-NH2 H-OH H-F increasing polarity Predicting Acid Strengths (when H is bonded to something other than oxygen) H-X where X varies across the period, acid strength depends on the polarity of H-X bond O N O O H O N O H HNO3 HNO2 Oxoacids with a differing number of oxygen atoms: Acid strength depends on Oxidation state of central atom +5 More e- withdrawing +3 Less e- withdrawing more ?glue?less ?glue? Section 12.5 Predicting Acid Strengths (when H is bonded to oxygen) Stronger acid Weaker acid > Predicting Acid Strengths (when H is bonded to oxygen) HClO4 HClO3 HClO2 HClO Section 12.5 O Cl O OO H O Cl OO H O Cl O H O Cl H... ... ...... More e- withdrawing Less e- withdrawing Stronger acid Weaker acid > > > Oxoacids with the same central atom: Acid strength depends on Oxidation state of central atom Predicting Acid Strengths (when H is bonded to oxygen) Oxoacids with a different central atom: Acid strength depends on Electronegativity of central atom HClO4 HBrO4 HIO4 Section 12.5 More EN center atom Less EN center atom Stronger acid Weaker acid > > O Cl O OO H O Br O OO H O I O OO H Predicting Acid Strengths - Summary For H-F, H-Cl, H-Br, and H-I: the strongest acid has the weakest bond H-I > H-Br > H-Cl > H-F Section 12.5 For H-F, H-OH, H-NH2, and H-CH3: the strongest acid has the most polar bond H-F > H-OH > H-NH2 > H-CH3 For Oxoacids with a differing number of oxygens: the strongest acid has the highest oxidation state (or most oxygen) HNO3 > HNO2 For Oxoacids with a different central atom : the strongest acid has the most electronegative central atom HClO4 > HBrO4 > HIO4 Lori Petrovich 11.7-12.2