Inorganic Pharmaceutical Analysis. Pharmacochemistry Research Group School of Pharmacy
|
|
- Hugo Woods
- 6 years ago
- Views:
Transcription
1 ACID BASE TITRATION An application method of Inorganic Pharmaceutical Analysis Lecturer : Dr. Tutus Gusdinar Pharmacochemistry Research Group School of Pharmacy INSTITUT TEKNOLOGI BANDUNG
2 The application of neutralization reaction Neutralization reaction could be used in determination of either natural or tried acid/basic analytes. Water is commonly used as a good solvent because of its cheap cost, easy to be obtained and prepared, non toxic, and low coeficient of expansion (Aquous Titration). Severalanalytescannotbetitrated analytes titrated inwater water, caused of its low solubility or too weak acid/base properties, these should be titrated in non aquaous solvent (Non Aquaous Titration).
3 Neutralization titration reagents Standard d acid solution o should oudbe standardized with a Primary Standard Bases suchas Na carbonate, TRIS atau THAM (tris hydroximethyl aminomethane), Natt tetraborate, t Mercuricoxide. id Standard basic solution (attention CO 2 effect to distilled water) should be standardized with a Primary Standard Acid such as KH Phtalate, Benzoic acid, Sulphamic acid, KH iodate, Sulphosalicilic li ili acid.
4 Sulfuric acid molecular model
5 ACID BASE INDICATORS
6 What is an acid base indicator? An acid base indicator is a weak acid or a weak base. The undissociated form of the indicator is a different color than the iogenic form of the indicator. An Indicator does not change color from pure acid to pure alkaline at specific hydrogen ion concentration, but rather, color change occurs over a range of hydrogen ion concentrations. This range is termed the color change interval. It is expressed as a ph range.
7 How is an indicator used? Weak acids are titrated in the presence of indicators which change under slightly alkaline conditions. Weak kbases should ldbe titrated t in the presence of indicators which change under slightly acidic conditions.
8 What are some common acid base indicators? Several acid base indicators are listed below, some more than once if they can be used over multiple ph ranges. Quantity of indicator in aqueous (aq.) or alcohol (alc.) solution is specified. Ti Tried and true d indicators include: thymol blue, tropeolin OO, methyl yellow, methyl orange, bromphenol blue, bromcresol green, methyl red, bromthymol blue, phenol red, neutral red, phenolphthalein, thymolphthalein, alizarin yellow, tropeolin O, nitramine, and trinitroben zoic acid. Data in this table are for sodium salts of thymol blue, bromphenol blue, tetrabromphenol blue, bromcresol green, methyl red, bromthymol blue, phenol red, and cresol red.
9 Acidic : HIn + H 2 O H 3 O + + In - Basic : In - + H 2 O HIn + OH - [H 3 O + ][In - ] [HIn] Ka = ph = pka - log [HIn] [In - ] End point colour depends to the most dominant concentration of such indicator form. Ex : if HIn is red and In - is yellow, then : At low ph in which [HIn] is dominant, the ratio of 10/1 (red). At high ph in which [In - ] is dominant, the ratio of 1/10 (yellow). At medium ph in which [HIn] = [In - ], the ratio of 1 (orange).
10 Indicator ph range Yll Yellow coloured solution : ph yellow = pka + log 10/1 = 5 +1 = 6 Red coloured solution : ph red = pka + log 1/10 = 5 11 = 4 ΔpH = ph yellow ph red = 2 ph range = 4 6
11 PHENOLPHTALEIN H 2 In HIn - HIn In -2
12 The first useful theory of indicator action was suggested by W. 0stwald based upon the concept that indicators in general use are very weak organic acids or bases. The simple Ostwald theory of the colour change of indicators has been revised, and the colour changes are believed to be due to structural t changes, including the production of quinonoid and resonance forms; these may be illustrated by reference to phenolphthalein, the changes of which are characteristic of all phthalein indicators. In the presence of dilute alkali the lactone ring in (I) opens to yield (II), and the triphenylcarbinol structure (II) undergoes loss of water to produce the resonating ion (III) which h is red. If phenolphthalein hth l is treated t with excess of concentrated alcoholic alkali the red colour first produced disappears owing to the formation of (IV).
13 The chemical structure change of phenolphtalein indicator
14 PHENOL RED H 2 In + (RED) HIn (YELLOW) In - (RED)
15 METHYL ORANGE ( HELIANTHINE ) HIn + (RED) In (YELLOW)
16 Acid Base indicators list NAME ph range pka (μ = 0,1 M) Thymol Blue COLOUR CHANGE Red Yellow Yellow Blue TYPE Acid Methyl Yellow Red Orange Basic Mehtyl Orange * Red Orange Basic Bromcresol Green Yellow Blue Acid Methyl Red * Red Yellow Basic Bromcresol Violet Yellow Violet Acid Bromthymol Blue Yellow Blue Acid Phenol Red Yellow Red Acid Cresol Violet Yellow Violet Acid Phenolphtalein Colourless Red Acid Thymolphtalein Colourless Blue Acid Alizarin Yellow Yellow Violet Basic
17 1 M 0.1 M 0.01 M
18 ALCALIMETRY
19 ACIDIMETRY
20 Mixed Indicator When sharp indicator colour change could not be obtained at the end point, a mixture of two indicators or an indicator mixture could be used. INDICATOR COLOUR CHANGE Methyl orange 1 gram violet grey green Indigo carmine 2.5 gram (acid) ph=4 (basic) Dissolved in 1 liter of water Bromcresol Green 01% part red green Methyl Red 0.1 % 2 part (acid) ph=5.1 (basic) Phenolphtalein 01% part green pale blue violet Methylene Green 0.1 % 2 part (acid) ph=8.8 (basic, ph>9) Cresol Red 0.1 % 1 part yellow pink violet Thymol Blue 0.1 % 3 part (acid) ph=8.2 (basic, ph>8.4) Cresol Red 0.1 % 16 ml MthlRd Methyl Red 01% ml Methylene Blue 0.2 % 4 ml green greenish grey greenish violet violet ph=8.85 ph=8.35 ph=8.6 ph=8.8
21 Carbonate Titration CO H + 3 O HCO 3 + H 2 O pka 2 = 6.34 HCO 3 + H 3 O + H 2 CO 3 + H 2 O pka 1 = By ΔpKa = 4.02 unit the equivalent point might be sharp, but Ka 1 is too low and a sharp equivalent point could not be obtained. Carbonate titration should be titrated with a strong acid using phenolphtalein indicator acid (ph = ) : ph NaHCO3 = ½ [pka 1 + pka 2 ] = 8.35 Methyl orange (ph = ) at the second equivalent point TE 2, saturated solution of CO 2 has ph = 3.9. The CO 2 gaz could be removed by these two techniques : Neutralization of sample using methyl orange indicator, or Removing CO 2 by boiling process of distilled water.
22 Titration ti curve of carbonate Phenolphtalein ph Methyl Orange ml HCl
23 Titration of Carbonate Bicarbonate Mixture First end point (phenolphtalein) : completed neutralization of NaOH, Na 2 CO 3 is half neutralized, HCO 3 has not reacted yet. Second end point t( (methyl orange) : all of HCO 3 was neutralized, small drops of titrant (HCl) can change the ph from 8 to 4 (could be corrected withindicatorblanco). indicator The mixture of NaOH + NaHCO 3 solution could not be prepared because of : HCO 3 + OH CO H 2 O The reaction results should be a mixture of HCO 3 + CO 2 3 or the only CO 2 3, depends on the relative amount of the compound content in a sample.
24 Titration curve of a mixture of carbonate + Bicarbonate OH - + H 3 O + H 2 O CO H 3 O + HCO H 2 O ph V 1 HCO H 3 O + H 2 CO 3 + H 2 O V ml HCl
25 Titration of mixed two acids Like as diprotic acid : [HX] initial = [HY] initial If HX (with its Ka 1 ) is strong acid and HY (with its Ka 2 ) is weak acid, then a feasible titration i can occured at pka 1 pka 2 > 4 unit For unequal initial concentration, first equivalent point could be calculated by such following steps : 1) Charge balance [Na + ] + [H 3 O + ] = [OH ] + [X ] + [Y ] 2) [Na + ] = acid formal concentration = [HX] + [X ] 3) 1)+2) : [H 3 O + ] = [OH ] + [Y ] [HX] 4) Substitute [OH ], [Y ] and [HX] from Kw, Ka 1, Ka 2 : [H 3 O + ] = Kw/ [H 3 O + ] + Ka 2 [HY]/[H 3 O + ] [H 3 O + ][X ]/Ka 1 5) [H 3 O + ] = {Ka 1 Kw + Ka 1 Ka 2 [HY]}/Ka 1 +[X ] 6) If Ka 2 [HY] >>>Kw and [X ] >>Ka 1 then [H 3 O + ] = Ka 1 Ka 2 [HY]/[X ] 7) ph = ½ (pka 1 + pka 2 ) ½ log [HY]/[X ]
26 Titration of mixed HCl + HAc HCl titrated first, ph is not influenced by H 3 O + from HAc [Le Chatelier principle p : excess proton will pressure weak acid dissociation]. This assumption is less valid at near the equivalent point, caused of excess proton concentration increases. At first equivalent point tthe HCl has all titrated t and theph depends d only to HAc dissociation. After first equivalent point HAc titrationwillstart start. Inthe next curve this first equivalent point is not clear because of lower (not enough) ΔpH/ΔV. While the ph of HAc M is about 3. Because of ph< 4 this titration i is not feasible (by using indicator). In the next step the weak acid titrated by strong base, the titration will be feasible. Example: Titration of 50 ml mixture of HCl 0.10 M and HAc 0.10 M with a solution of NaOH 0.10M.
27 Titration curve of acids mixture 50 ml of HCl 0,10 M and HAc 0.10 M (Ka= ) titrated with NaOH 0.20 M ph 50 ml of HCl 0,10 M and HX 0.10 M (Ka= ) titrated with NaOH 0.20 M ml NaOH
28 TITRATION ERROR A feasible titration can be performed in a complete reaction at the end point, resulting a sharp ph depletion (vertical curve). A complete reaction should be obtained in a high value of K (equilibrium constant), great change of ph at near to end point, to obtain easily a high precision of the end point.
29 Titration of strong acid with strong base gives a very high K value : H O + OH H 2 O K = 1/Kw = 10 A high ΔpH occurs at equivalent point, i.e unit ph for a Δ V = 0.10 ml. At this high ΔpH any indicator could be used for obtaining a high precision of titration (ppm). This is a feasible titration. But it is difficult to calculate exactly the K value for a feasible titration, because of the influence of analyte and titrant concentrations to the ΔpH. In certain condition, titration could be perform without high precision.
30 It is predicted about 99.9% and 99.99% of analyte changes to its reaction product at the equivalent point. At this condition the K value could be predicted. There is a limited ability of human eyes to observe indicator colour change at the equivalent point, a few drops of titrant could change ph of 1 2 unit. Example : Titration of 50 ml HA 0.10 M with a strong base of 0.1 M. Calculate K minimum at an addition of ml titran (complete reaction), when addition of 2 drops (0,10 ml) of titrant after equivalent point changes ph at units. What is K minimum at ph change of 1 unit?
31 Influence of analyte and titrant concentration : ΔpH H decreases if the concentration ti of analyte lt and titrant decrease. Example : Weak acid titration : low of Ka, high of ph equivalent point and low of ΔpH. Increasing [HA] will decrease ΔpH. Increasing titrant volume should increase titration error. (resulting a smaller value than true end point). If [HA] is titrated at a smaller initial volume, then ΔpH increases, caused by little excessive titrant volume. If [titrant] increases then ΔpH increases, this diminues titrant Volume and increases titration error (higher than true end point).
32 In general: Precision (at ppm) could be produced by titration of weak acid/base solution of 0.05 M (dissociation constant of 1x10 6 M) with a titrant solution of M (K = 1x10 8). Salts of weak acid (Bronsted base) could be feasibly titrated by strong acid when its conjugated acid is too weak.
33 Example : An acid HA (Ka = 1x ) is too weak for a titration with a base which has dissociation constant of its conjugate base A = 1x10 5, because of Ka x Kb = 1x A could be titrated by strong acid. Same case for a weak base and its salt.
34 Titration error is the difference of reagent amount used between end point and equivalent point, in % oro/ooof o/oo of reacted compound equivalent quantity. Titration of strong acid of 0.01 N with a strong base gives an error of % at ph 5 or 9; but this error will be % at ph 6 or 8. Lower titration error should be obtained in a titration of carboxilic acid (Ka > 10 5 ) with a strong base. If Ca = acid analytical concentration and Cb = standad base analytical concentration, then at the equivalent point Ca = Cb, at the other points : Ca Cb = + or as titration error. During titration : Ca = [HA] + [A ] and Cb = [A ] + [OH ] [H + ] If weak base solution (near equivalent point) and [H + ] are neglected, hence Ca = Cb = [A ] + [HA] = [A ] + [OH ] [HA] = [OH ]
35 At equivalent point a pure cmpound NaA dissociates A + H 2 O HA + OH If acetic acid titration (Ka = 1.8 x ) without a significant volume Change, error at end point + 1 from equivelent point, At the equivalent point [HA] = [OH ] = 7.5 x 10 6 M ph = 8.8 If equivalent point occured at ph = 9.88 (or ph = 9.9) hence [HA] = 7 x 10 7 M or [OH ] = 76 x 10 5 Titration error = Cb Ca = {[OH ] [HA]}/Ca x 100% = 0.07%. If colour change at the equivalent point is clear and sharp, and the indicator is very good, titration error could be neglected.
36 Titration of Heavy Metal Cations An aquaous solution of heavy metal is a base (Bronsted), titrated witha strong base form an insoluble saltbase. Al OH Al(OH) 3 white precipitate i Cu OH Cu(OH) 2 blue precipitate The end point could be obtained before equivalent point caused of the early precipitated saltbase base. Itis beter to performe this withan indirect titration technique.
37 Titration of Borate (Borax) A borate (borax) dissolved in water could form a half neutralized boric acid Na 2 B 4 O H 2 O 2 H 3 BO H 2 BO Na + 2 H 2 BO H + 2 H 3 BO 3 A sharp end point should be obtained, this is an appropriate primary standard base for a standardization of HCl.
38 Titration of phosphoric acid Titration of phosphoric acid with NaOH is a mono/di protic (not triprotic) Eq point 1 : ph = ½ (pka 1 + pka 2 ) = 4.66 Indicator bromcresol green or methyl yellow. End point in detected using pure NaH 2 PO 4 as control compound. Eq point 2 : ph = ½ (pka 2 + pka 3 ) = 9.7 Indicator phenolphtalein orthymolblue blue, colour change occures in basic solution before equivalent point. Indicator timolphtalein would be better because of ph = 9.6 Third ionization product of phosphoric acid has Ka = 5 x Solution ofna 3 PO 4 is strong basic andeq. Point 3 is never obtained, except trivalent phosphate ion is removed such by CaCl 2 precipitation after Eq.Point 2 2 Na 2 HPO CaCl 2 Ca 3 (PO 4 ) NaCl + 2 HCl
39 Titration of carbonic acid (hydrated CO 2 ) As a diprotic acid : ph = ½ (pka1 + pka2) = 8.40 At Eq Point 1 the CO 2 could be titrated as monoprotic acid with a solution of NaOH using phenolphtalein or thymol blue (or its mixture), colour change is not sharp, needs control solution (pure NaHCO 3 + indicator at same quantity as for sample). Second ionization product, as a weak diprotic acid is too week for a direct titration. Carbonate ion has to be removed (precipitation) by addition of excess Ba(OH) 2 H 2 CO 3 + Ba(OH) 2 NaHCO 3 + Ba(OH) 2 BaCO 3 + 2H 2 O BaCO 3 + NaOH + H 2 O
40 Back titration with an acid standard solution could use phenolphtalein or thymol blue as the indicator without any filtering process. BaCO 3. NaHCO 3 Na 2 CO 3 H 2 CO 3 + NaHCO 3 ph NaHCO 3 + Na 2 CO ml NaOH 0.1 N Titration curve of 100 ml of carbonic acid 0.05 M with NaOH 0.1N
41 Summary Choice of indicator
42 Strong acid and strong base. For 0.1 M or more concentrated solutions, any indicator may be used which has a range between the limits ph 4.5 and ph 9.5. With 0.01 M solutions, the ph range is somewhat smaller ( ). If carbon dioxide is present, either the solution should be boiled while still acid and the solution titrated when cold, or an indicator with a range below ph 5 should be employed.
43 Weak acid and a strong base. The ph at the equivalence point is calculated from the equation: ph = ½ pkw + ½ pka ½ pc The ph range for acids with Ka > 10-5 is ; for weaker acids (Ka >10-6 ) the range is reduced (8-10). The ph range will cover most of the examples likely to be encountered; this permits the use of thymol blue, thymolphthalein, or phenolphthalein. hth l
44 Weak base and strong acid. The ph at the equivalence point is computed from the equation: ph = ½ pkw ½ pkb + ½ pc The ph range for bases with Kb > 10-5 is 3-7 7, and for weaker bases (Kb > 10-6 ) 3-5. Suitable indicators will be methyl red, methyl orange, methyl yellow, bromocresol green, and bromophenol blue.
45 Weak acid and weak base. There is no sharp rise in the neutralisation curve and, generally, no simple indicator can be used. The titration should therefore be avoided, if possible. The approximate ph at the equivalence point can be computed from the equation : ph = ½ pkw + ½ pka ½ pkb It is sometimes possible to employ a mixed indicator which exhibits a colour change over a very limited it ph range, for example, neutral red-methylene blue for dilute ammonia solution and acetic (ethanoic) acid.
46 Polyprotic acids (or mixtures of acids, with dissociation constants K 1, K 2, and K 3 ) and strong bases. The first stoichiometric end point is given approximately by ph = ½ (pk 1 + pk 2 ) The second stoichiometric end point is given approximately by ph = ½ (pk 2 + pk 3 )
47 Anion of a weak acid titrated with a strong acid. The ph at the equivalence point is given by ph = ½ pkw ½ pka ½ pc Cation of a weak base titrated with a strong base. The ph at the stoichiometric end point is given by ph = ½ pkw ½ pkb ½ pc
48 As a general rule, wherever an indicator does not give a sharp end point, it is advisable to prepare an equal volume of a comparison solution containing the same quantity of indicator and of the final products and other components of the titration i as in the solution under test, and to titrate to the colour shade thus obtained. In cases where it proves impossible to find a suitable indicator (and this will occur when dealing with strongly coloured solutions) then titration may be possible by an electrometric method such as conductimetric, potentiometric or amperometric titration. In some instances, spectrophotometric titration may be feasible. It should also be noted that if it is possible to work in a non-aqueous solution rather than in water, then acidic and basic properties may be altered according to the solvent chosen, and titrations which are difficult in aqueous solution may then become easy to perform. This procedure is widely used for the analysis of organic materials but is of very limited application with inorganic substances.
49 End
UNIT 8 NEUTRALIZATION TITRATION-I
UNIT 8 NEUTRALIZATION TITRATION-I Structure 8.1 Introduction Objectives 8. Basic Concepts of Titrimetry, Primary and Secondary Standards 8.3 Titration Curves Titration of A Strong Acid Versus Strong Base
More informationChapter 17 Answers. Practice Examples [H3O ] 0.018M, 1a. HF = M. 1b. 30 drops. 2a.
Chapter 17 Answers Practice Examples 1a. + [HO ] 0.018M, 1b. 0 drops [HF] = 0.8 M. [H O + ] = 0.10 M, HF = 0.97 M. a. + HO 1.10 M, CHO = 0.150 M. b. 15g NaCHO a. The hydronium ion and the acetate ion react
More informationChemical Equilibria Part 2
Unit 1 - Inorganic & Physical Chemistry 1.4 Chemical Equilibria Part 2 Acid / Base Equilibria Indicators ph Curves Buffer Solutions Pupil Notes Learning Outcomes Questions & Answers KHS ChemistrySept 2015
More informationAcids, Bases and the Common Ion Effect. More quantitative. Continued [F - ] = M. Consider the following acid equilibrium of a weak acid:
Acids, Bases and the Common Ion Effect Consider the following acid equilibrium of a weak acid: HF + H O H 3 O + + F - K a = [H 3 O + ][F - ] [HF] By LeChatelier s principle, we predict the HF dissociation
More informationAcid Base Review Package
Acid Base Review Package 1. In which of the following eqb systems is HCO 3 acting as a BronstedLowry base? 2 a. HCO 3 H+ + CO 3 b. HCO 3 + HS 2 H 2 S + CO 3 c. HCO 3 + H 2 S H 2 CO 3 + HS d. HCO 3 + H
More informationPharmaceutical Analytical Chemistry (PHCM223-SS16) Lecture 5 ACID- BASE EQUILIBRIUM-V ph indicators
Pharmaceutical Analytical Chemistry (PHCM223-SS16) Lecture 5 ACID- BASE EQUILIBRIUM-V ph indicators Dr. Rasha Hanafi PHCM223,SS16 Lecture 5, Dr. Rasha Hanafi 1 LEARNING OUTCOMES By the end of this session
More informationGrade A buffer: is a solution that resists changes in its ph upon small additions of acid or base.sq1
Chapter 15 Lesson Plan Grade 12 402. The presence of a common ion decreases the dissociation. BQ1 Calculate the ph of 0.10M CH 3 COOH. Ka = 1.8 10-5. [H + ] = = ( )( ) = 1.34 10-3 M ph = 2.87 Calculate
More informationph calculations MUDr. Jan Pláteník, PhD Brønsted-Lowry concept of acids and bases Acid is a proton donor Base is a proton acceptor
ph calculations MUDr. Jan Pláteník, PhD Brønsted-Lowry concept of acids and bases Acid is a proton donor Base is a proton acceptor HCl(aq) + H 2 O(l) H 3 O + (aq) + Cl - (aq) Acid Base Conjugate acid Conjugate
More informationQuestions #4-5 The following two questions refer to the following system: A 1.0L solution contains 0.25M HF and 0.60M NaF (Ka for HF = 7.2 x 10-4 ).
Multiple Choice 1) A solution contains 0.250 M HA (K a = 1.0 x 10-6 ) and 0.45 M NaA. What is the ph after 0.10 mole of HCl is added to 1.00L of this solution? a. 3.17 b. 3.23 c. 6.00 d. 10.77 e. 10.83
More informationHomework: 14, 16, 21, 23, 27, 29, 39, 43, 48, 49, 51, 53, 55, 57, 59, 67, 69, 71, 77, 81, 85, 91, 93, 97, 99, 104b, 105, 107
Homework: 14, 16, 21, 23, 27, 29, 39, 43, 48, 49, 51, 53, 55, 57, 59, 67, 69, 71, 77, 81, 85, 91, 93, 97, 99, 104b, 105, 107 Chapter 15 Applications of Aqueous Equilibria (mainly acid/base & solubility)
More informationmol of added base 36. Equal moles of which of the following chemicals could be used to make a basic (1 mark)
59. 34. Consider the following titration curve: 14 13 Consider the following titration curve: 14 1 13 11 14 1 1 13 119 1 18 ph 119 7 18 6 ph 97 5 86 4 ph 75 3 64 53 1 4 31 mol of added base Select a suitable
More information( 1 ) Concept of acid / base
Section 6.2 Ionic Equilibrium Unit 628 ( 1 ) Concept of acid / base The best definition of acids and bases is that proposed by T.M. Lowry and also, independently by J.N. Bronsted in 1923. BronstedLowry
More informationEdexcel Chemistry A-level Topic 12 - Acid-Base Equilibria
Edexcel Chemistry A-level Topic 12 - Acid-Base Equilibria Flashcards Define a Bronsted-Lowry acid Define a Bronsted-Lowry acid Proton donor Define a Bronsted-Lowry base Define a Bronsted-Lowry base Proton
More informationAcids and Bases Written Response
Acids and Bases Written Response January 1999 4. Consider the salt sodium oxalate, Na2C2O4. a) Write the dissociation equation for sodium oxalate. (1 mark) b) A 1.0M solution of sodium oxalate turns pink
More informationWorksheet 4.1 Conjugate Acid-Base Pairs
Worksheet 4.1 Conjugate AcidBase Pairs 1. List five properties of acids that are in your textbook. Acids conduct electricity, taste sour, neutralize bases, change the color of indicators, and react with
More informationChapter 15. Titration Curves for Complex Acid/Base Systems
Chapter 15 Titration Curves for Complex Acid/Base Systems Polyfunctional acids and bases Carbonic acid/bicarbonate buffer system Buffers for human blood ph = 7.35-7.45 CO 2(g) + H 2 O H 2 CO 3(aq) H 2
More informationAcids And Bases. H + (aq) + Cl (aq) ARRHENIUS THEORY
Acids And Bases A. Characteristics of Acids and Bases 1. Acids and bases are both ionic compounds that are dissolved in water. Since acids and bases both form ionic solutions, their solutions conduct electricity
More information4.3 ANSWERS TO EXAM QUESTIONS
4. ANSWERS TO EXAM QUESTIONS. (a) (i) A proton donor () (ii) Fully ionised or fully dissociated () (iii) 0 0 4 () mol dm 6 () 4 (b) (i) 50 0 /5 000 () = 0 06 mol dm () () (ii) Mol OH added = 50 0 50/000
More informationCHAPTER 7.0: IONIC EQUILIBRIA
Acids and Bases 1 CHAPTER 7.0: IONIC EQUILIBRIA 7.1: Acids and bases Learning outcomes: At the end of this lesson, students should be able to: Define acid and base according to Arrhenius, Bronsted- Lowry
More informationAcids, Bases and the Common Ion Effect
cids, Bases and the Common Ion Effect Consider the following acid equilibrium of a weak acid: HF + H O H 3 O + + F By LeChatelier s principle, we predict the HF dissociation should be driven left, suppressing
More information1.12 Acid Base Equilibria
.2 Acid Base Equilibria BronstedLowry Definition of acid Base behaviour A BronstedLowry acid is defined as a substance that can donate a proton. A BronstedLowry base is defined as a substance that can
More informationAP Chemistry. CHAPTER 17- Buffers and Ksp 17.1 The Common Ion Effect Buffered Solutions. Composition and Action of Buffered Solutions
AP Chemistry CHAPTER 17- Buffers and Ksp 17.1 The Common Ion Effect The dissociation of a weak electrolyte is decreased by the addition of a strong electrolyte that has an ion in common with the weak electrolyte.
More information12. Acid Base Equilibria
2. Acid Base Equilibria BronstedLowry Definition of acid Base behaviour A BronstedLowry acid is defined as a substance that can donate a proton. A BronstedLowry base is defined as a substance that can
More information10.1 Acids and Bases in Aqueous Solution
10.1 Acids and Bases in Aqueous Solution Arrhenius Definition of Acids and Bases An acid is a substance that gives hydrogen ions, H +, when dissolved in water. In fact, H + reacts with water and produces
More informationUnderstanding the shapes of acid-base titration curves AP Chemistry
Understanding the shapes of acidbase titration curves AP Chemistry Neutralization Reactions go to Completion Every acidbase reaction produces another acid and another base. A neutralization reaction is
More informationBuffers. A buffered solution resists changes in ph when small amounts of acids or bases are added or when dilution occurs.
Buffers A buffered solution resists changes in ph when small amounts of acids or bases are added or when dilution occurs. The buffer consists of a mixture of an acid and its conjugate base. Example: acetic
More informationCHM 112 Dr. Kevin Moore
CHM 112 Dr. Kevin Moore Reaction of an acid with a known concentration of base to determine the exact amount of the acid Requires that the equilibrium of the reaction be significantly to the right Determination
More informationUnit 9: Acids, Bases, & Salts
STUDENT VERSION Unit 9: Acids, Bases, & Salts Unit Vocabulary: Arrhenius acid Arrhenius base Bronsted-Lowry acid Bronsted-Lowry base Electrolyte hydronium ion hydroxide ion indicator (acid/base) neutralization
More informationmohd faisol mansor/chemistry form 4/chapter 7 CHAPTER 7 ACIDS AND BASES HCl (g) H 2 O H + (aq) + Cl - (aq) NaOH(s) H 2 O Na + (aq) + OH - (aq)
CHAPTER 7 ACIDS AND BASES Arrhenius Theory An acid is a chemical compound that produces hydrogen ions, H + or hydroxonium ions H3O + when dissolve in water. A base defined as a chemical substance that
More informationAcids and Bases Written Response
Acids and Bases Written Response January 1999 4. Consider the salt sodium oxalate, Na2C2O4. a) Write the dissociation equation for sodium oxalate. (1 mark) b) A 1.0M solution of sodium oxalate turns pink
More informationProton Transfer Acids - Base. Dr. Fred Omega Garces Chemistry 201. Miramar College
16.2 Acids Base Proton Transfer Dr. Fred Omega Garces Chemistry 201 Miramar College Important Notes: K a when H 3 O + is produced, K b when OH is produced 1 Acids Bases; Proton Transfer BrønstedLowry AcidsBases
More informationChemistry 102 Chapter 17 COMMON ION EFFECT
COMMON ION EFFECT Common ion effect is the shift in equilibrium caused by the addition of an ion that takes part in the equilibrium. For example, consider the effect of adding HCl to a solution of acetic
More informationTHEORY OF INDICATORS
THEORY OF INDICATORS Methods to determine the end point Visual indicators: Colour change: In some reactions, the solution changes colour without any added indicator. This is often seen in redox titrations,
More informationCHAPTER 7 Acid Base Equilibria
1 CHAPTER 7 Acid Base Equilibria Learning Objectives Acid base theories Acid base equilibria in water Weak acids and bases Salts of weak acids and bases Buffers Logarithmic concentration diagrams 2 ACID
More informationChapter 17. Additional Aspects of Equilibrium
Chapter 17. Additional Aspects of Equilibrium 17.1 The Common Ion Effect The dissociation of a weak electrolyte is decreased by the addition of a strong electrolyte that has an ion in common with the weak
More informationLesmahagow High School AHChemistry Inorganic and Physical Chemistry Lesmahagow High School CfE Advanced Higher Chemistry
Lesmahagow High School CfE Advanced Higher Chemistry Unit 1 Inorganic and Physical Chemistry Chemical Equilibrium 1 Dynamic Equilibrium Revision Dynamic equilibrium happens in a closed system when the
More informationMake a mixture of a weak acid and its conjugate base (as the SALT) Make a mixture of a weak base and its conjugate acid (as the SALT)
175 BUFFERS - resist ph change caused by either the addition of strong acid/base OR by dilution Made in one of two ways: Make a mixture of a weak acid and its conjugate base (as the SALT) Make a mixture
More information4. Acid Base Equilibria
4. Acid Base Equilibria BronstedLowry Definition of acid Base behaviour A BronstedLowry acid is defined as a substance that can donate a proton. A BronstedLowry base is defined as a substance that can
More informationUnit Nine Notes N C U9
Unit Nine Notes N C U9 I. AcidBase Theories A. Arrhenius Acids and Bases 1. Acids contain hydronium ions (H O ) commonly referred to as hydrogen ions (H ) that dissociate in water a. Different acids release
More informationAcid-Base Equilibria. And the beat goes on Buffer solutions Titrations
Acid-Base Equilibria And the beat goes on Buffer solutions Titrations 1 Common Ion Effect The shift in equilibrium due to addition of a compound having an ion in common with the dissolved substance. 2
More informationAcids Bases and Salts Acid
Acids Bases and Salts Acid ph less than 7.0 Sour taste Electrolyte Names of Acids Binary acids Contain only 2 elements Begin with hydro; end with ic Ternary acids Ex: H 2 S = hydrosulfuric Contain a polyatomic
More information5.1.3 Acids, Bases and Buffers
5..3 Acids, Bases and Buffers BronstedLowry Definition of Acid Base behaviour A BronstedLowry acid is defined as a substance that can donate a proton. A BronstedLowry base is defined as a substance that
More informationIB Chemistry ABS Introduction An acid was initially considered a substance that would produce H + ions in water.
IB Chemistry ABS Introduction An acid was initially considered a substance that would produce H + ions in water. The Brønsted-Lowry definition of an acid is a species that can donate an H + ion to any
More informationUnit 4: ACIDS, BASES AND SALTS
ABS - 1 Unit 4: ACIDS, BASES AND SALTS 4.1 Arrhenius Acids and Bases Acids release H + in water Bases release OH - in water Salts are products of an acid-base neutralization reaction. The salt is an ionic
More informationAcids and bases, ph and buffers. Dr. Mamoun Ahram Lecture 2
Acids and bases, ph and buffers Dr. Mamoun Ahram Lecture 2 ACIDS AND BASES Acids versus bases Acid: a substance that produces H+ when dissolved in water (e.g., HCl, H2SO4) Base: a substance that produces
More informationACIDS AND BASES. HCl(g) = hydrogen chloride HCl(aq) = hydrochloric acid HCl(g) H + (aq) + Cl (aq) ARRHENIUS THEORY
ACIDS AND BASES A. CHARACTERISTICS OF ACIDS AND BASES 1. Acids and bases are both ionic compounds that are dissolved in water. Since acids and bases both form ionic solutions, their solutions conduct electricity
More informationEXPT. 4 DETERMINATION OF pka OF ORTHOPHOSPHORIC ACID
EXPT. DETERMINATION OF pka OF ORTHOPHOSPHORIC ACID Structure.1 Introduction Objectives.2 Principle.3 Requirements. Solutions Provided.5 Procedure.6 Observations and Calculations.7 Result.1 INTRODUCTION
More informationAcids, Bases, & Neutralization Chapter 20 & 21 Assignment & Problem Set
Acids, Bases, & Neutralization Name Warm-Ups (Show your work for credit) Date 1. Date 2. Date 3. Date 4. Date 5. Date 6. Date 7. Date 8. Acids, Bases, & Neutralization 2 Study Guide: Things You Must Know
More information1 Chapter 19 Acids, Bases, and Salts
1 Chapter 19 Acids, Bases, and Salts ACID-BASE THEORIES Acids and bases are all around us and part of our everyday life (ex. bodily functions, vinegar, carbonated drinks, citrus fruits, car batteries,
More informationA 95 g/mol B 102 /mol C 117 g/mol D 126 g/mol E 152 g/mol
Titrations In a titration a solution of accurately known concentration is added gradually added to another solution of unknown concentration until the chemical reaction between the two solutions is complete.
More informationEXPERIMENT. Estimate the strength of given sodium carbonate solution by titrating it against HCl solution using methyl orange as indicator.
EXPERIMENT AIM Estimate the strength of given sodium carbonate solution by titrating it against HCl solution using methyl orange as indicator. Approximately M/40 HCl solution is provided. Prepare your
More informationnot to be republished NCERT YOU are already aware that a substance is analysed to establish its qualitative TITRIMETRIC ANALYSIS UNIT-6
UNIT-6 TITRIMETRIC ANALYSIS YOU are already aware that a substance is analysed to establish its qualitative and quantitative chemical composition. Thus, chemical analysis can be categorised as qualitative
More informationbattery acid the most widely used industrial chemical Hydrochloric acid, HCl muriatic acid stomach acid Nitric acid, HNO 3
BRCC CHM 101 Chapter 9 Notes (Chapter 8 in older text versions) Page 1 of 9 Chapter 9: Acids and Bases Arrhenius Definitions more than 100 years old Acid a substance that produces H + in water (H + is
More informationName: Date: Period: #: TITRATION NOTES
TITRATION NOTES I. Titration and Curves - Titration: lab technique in which one solution is used to analyze another (analyte/titrant) - point: point in a titration where just enough standard solution has
More informationAcid-Base Titrations. Terms. Terms. Terms
Isoionic Point: The ph of pure, neutral polyprotic acid (the natural zwitterion) HAwater: H A +, A -, H +, and OH - Most HA and [H A + ][A - ] Isoelectric Point: ph at which the average charge of the polyprotic
More informationChapter 10 - Acids & Bases
Chapter 10 - Acids & Bases 10.1-Acids & Bases: Definitions Arrhenius Definitions Acids: substances that produce hydrogen ions when dissolved in H 2 O Common Strong Acids: Common Weak acids: Organic carboxylic
More informationChemistry Lab Equilibrium Practice Test
Chemistry Lab Equilibrium Practice Test Basic Concepts of Equilibrium and Le Chatelier s Principle 1. Which statement is correct about a system at equilibrium? (A) The forward and reverse reactions occur
More information(14) WMP/Jun10/CHEM4
Acids, Bases and ph 14 5 In this question, give all values of ph to two decimal places. Calculating the ph of aqueous solutions can involve the use of equilibrium constants such as K w and K a K w is the
More informationOCR (A) Chemistry A-level Topic Acids, Bases and Buffers
OCR (A) Chemistry A-level Topic 5.1.3 - Acids, Bases and Buffers Flashcards Define a Bronsted-Lowry acid Define a Bronsted-Lowry acid Proton donor Define a Bronsted-Lowry base Define a Bronsted-Lowry base
More informationIntroduction to Analytical Chemistry
Introduction to Analytical Chemistry ANALYTICAL CHEMISTRY: The Science of Chemical Measurements. ANALYTE: The compound or chemical species to be measured, separated or studied TYPES of ANALYTICAL METHODS:
More informationChapter 15. Acid-Base Equilibria
Chapter 15 Acid-Base Equilibria The Common Ion Effect The common-ion effect is the shift in an ionic equilibrium caused by the addition of a solute that provides an ion already involved in the equilibrium
More informationI II III IV. Volume HCl added. 1. An equation representing the reaction of a weak acid with water is
1. An equation representing the reaction of a weak acid with water is A. HCl + H 2 O H 3 O + + Cl B. NH 3 + H 2 O NH 4 + + OH C. HCO 3 H 2 O H 2 CO 3 + OH D. HCOOH + H 2 O H 3 O + + HCOO 2. The equilibrium
More informationKEY. Practice Problems: Applications of Aqueous Equilibria
Practice Problems: Applications of Aqueous Equilibria KEY CHEM 1B 1. Ammonia (NH3) is a weak base with a Kb = 1.8 x 1 5. a) Write the balanced chemical equation for the reaction of ammonia with water.
More informationChapter 14. Principles of Neutralization Titrations
Chapter 14 Principles of Neutralization Titrations Neutralization titrations are widely used to determine the amounts of acids and bases and to monitor the progress of reactions that produce or consume
More informationAcids and Bases. Acid. Acid Base 2016 OTHS. Acid Properties. A compound that produces H + ions when dissolved in water. Examples!
Acids and Bases Acid A compound that produces H + ions when dissolved in water. Examples! Vinegar Acetic acid Lemon Juice Citric acid Sour Candy Malic acid (and others) Milk Lactic acid HCl(aq) Acid Properties
More informationREPORT FORM ACID BASE EQUILIBRIA. Name
REPORT FORM ACID BASE EQUILIBRIA Name Section A Write chemical equations to explain the results of the conductance experiments demonstrated by your instructor. Only write equations for conductive solutions.
More informationUnit #6, Chapter 8 Outline Acids, Bases and ph
Lesson Topics Covered 1&2 Review of Acids from Grade 11 Arrhenius acids and bases, definition chemical properties of acids & bases naming acids and bases Unit #6, Chapter 8 Outline Acids, Bases and ph
More informationChem 1046 Lecture Notes Chapter 17
Chem 1046 Lecture Notes Chapter 17 Updated 01-Oct-2012 The Chemistry of Acids and Bases These Notes are to SUPPLIMENT the Text, They do NOT Replace reading the Text Book Material. Additional material that
More informationIonic Equilibria. In the Brönsted Lowry classification, acids and bases may be anions such as HSO 4
Ionic Equilibria Brönsted Lowry Theory According to the Brönsted Lowry theory, an acid is a substance, charged or uncharged, that is capable of donating a proton, and a base is a substance, charged or
More informationChapter 17. Additional Aspects of Equilibrium
Chapter 17. Additional Aspects of Equilibrium 17.1 The Common Ion Effect The dissociation of a weak electrolyte is decreased by the addition of a strong electrolyte that has an ion in common with the weak
More informationAP Chapter 15 & 16: Acid-Base Equilibria Name
AP Chapter 15 & 16: Acid-Base Equilibria Name Warm-Ups (Show your work for credit) Date 1. Date 2. Date 3. Date 4. Date 5. Date 6. Date 7. Date 8. AP Chapter 15 & 16: Acid-Base Equilibria 2 Warm-Ups (Show
More information1.8K: Define a buffer as relatively large amounts of a weak acid or base and its conjugate in equilibrium that maintain a relatively constant ph when
1.8K: Define a buffer as relatively large amounts of a weak acid or base and its conjugate in equilibrium that maintain a relatively constant ph when small amounts of acid or base are added. 1 Chem 20
More informationAcids, Bases and Buffers
1 Acids, Bases and Buffers Strong vs weak acids and bases Equilibrium as it relates to acids and bases ph scale: [H+(aq)] to ph, poh, etc ph of weak acids ph of strong acids Conceptual about oxides (for
More information1. What colour would 1.0 M HCl be in an indicator mixture consisting of phenol red and
cids Practice Test 2 1. What colour would 1.0 M Hl be in an indicator mixture consisting of phenol red and thymolphthalein? red blue yellow colourless 2. uring a titration, what volume of 0.500 M KOH is
More informationCHEMISTRY - BURDGE-ATOMS FIRST 3E CH.17 - ACID-BASE EQUILIBRIA AND SOLUBILITY EQUILIBRIA
!! www.clutchprep.com CONCEPT: CLASSIFICATION AND IDENTIFICATION OF BUFFERS Solutions which contain a acid and its base are called buffer solutions because they resist drastic changes in ph. They resist
More informationADVANCED PLACEMENT CHEMISTRY ACIDS, BASES, AND AQUEOUS EQUILIBRIA
ADVANCED PLACEMENT CHEMISTRY ACIDS, BASES, AND AQUEOUS EQUILIBRIA Acids- taste sour Bases(alkali)- taste bitter and feel slippery Arrhenius concept- acids produce hydrogen ions in aqueous solution while
More information(for tutoring, homework help, or help with online classes)
www.tutor-homework.com (for tutoring, homework help, or help with online classes) 1. Question 10 37 In the following reaction, SO 2 (g) + CuO(s) ----> Cu(s) + SO 3 (g), sulfur dioxide reduce copper(ii)
More information1. What do a chemical indicator and a buffer solution typically both contain?
Acids, Bases & Redox 2 - Practice Problems for Assignment 9 1. What do a chemical indicator and a buffer solution typically both contain? (a) A strong acid and its conjugate acid (b) A strong acid and
More informationPublic Review - Acids and Bases. June A solution of which ph would make red litmus paper turn blue? (A) 2 (B) 4 (C) 6 (D) 8
Public Review Acids and Bases June 2005 13. A solution of which ph would make red litmus paper turn blue? 2 4 6 8 14. Which is the most recent definition of an acid? Arrhenius Brønsted)Lowry modified Arrhenius
More informationGrace King High School Chemistry Test Review
CHAPTER 19 Acids, Bases & Salts 1. ACIDS Grace King High School Chemistry Test Review UNITS 7 SOLUTIONS &ACIDS & BASES Arrhenius definition of Acid: Contain Hydrogen and produce Hydrogen ion (aka proton),
More informationReview: Acid-Base Chemistry. Title
Review: Acid-Base Chemistry Title Basics General properties of acids & bases Balance neutralization equations SA + SB water + salt Arrhenius vs. Bronsted-Lowry BL plays doubles tennis match with H+) Identify
More informationDr. Diala Abu-Hassan, DDS, PhD Lecture 3 MD summer 2014
ph, DDS, PhD Dr.abuhassand@gmail.com Lecture 3 MD summer 2014 www.chem4kids.com 1 Outline ph Henderson-Hasselbalch Equation Monoprotic and polyprotic acids Titration 2 Measuring the acidity of solutions,
More informationACID-BASE EQUILIBRIA. Chapter 14 Big Idea Six
ACID-BASE EQUILIBRIA Chapter 14 Big Idea Six Acid-Base Equilibria Common Ion Effect in Acids and Bases Buffer SoluDons for Controlling ph Buffer Capacity ph-titradon Curves Acid-Base TitraDon Indicators
More informationPractice Problems: Applications of Aqueous Equilibria
Practice Problems: Applications of Aqueous Equilibria CHEM 1B 1. Ammonia (NH3) is a weak base with a Kb = 1.8 x 1 5. a) Write the balanced chemical equation for the reaction of ammonia with water. Using
More informationChem 103 Exam #1. Identify the letter of the choice that best completes the statement or answers the question. Multiple Choice
Chem 103 Exam #1 Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. Which of the following can act as a Bronsted-Lowry base, but not as a Bronsted-Lowry
More informationMore reaction types. combustions and acid/base neutralizations
More reaction types combustions and acid/base neutralizations Combustion reactions C x H y + O 2(g) CO 2(g) + H 2 O (l) + E If the hydrocarbon contains nitrogen as well C x H y N z + O 2(g) CO 2(g) + H
More information14-Jul-12 Chemsheets A
www.chemsheets.co.uk 14-Jul-12 Chemsheets A2 009 1 BRONSTED-LOWRY ACIDS & BASES Bronsted-Lowry acid = proton donor (H + = proton) Bronsted-Lowry base = proton acceptor (H + = proton) Bronsted-Lowry acid-base
More informationChapter 16: Applications of Aqueous Equilibrium Part 2. Acid-Base Titrations
Chapter 16: Applications of Aqueous Equilibrium Part 2 Acid-Base Titrations When you add an acid and a base together, a neutralization rxn occurs. In the lab, we do neutralization rxns all the time as
More informationChem12 Acids : M.C
Chem12 Acids : M.C. 3-260 1) The equation showing the acid form of an indicator reacting with a basic solution is : a) In - (aq) + OH - (aq) -> HIn(aq) + O 2- (aq) b) HIn(aq) + OH - (aq) ->H 2 O(l) + In
More informationChapter 17 Additional Aspects of Aqueous Equilibria (Part A)
Chapter 17 Additional Aspects of Aqueous Equilibria (Part A) What is a dominant equilibrium? How do we define major species? Reactions between acids and bases 1. Strong Acids + Strong Base The reaction
More information*KEY* * KEY * Mr. Dolgos Regents Chemistry. NOTE PACKET Unit 9: Acids, Bases, & Salts
*KEY* * KEY * Mr. Dolgos Regents Chemistry NOTE PACKET Unit 9: Acids, Bases, & Salts 1 *KEY* Unit 9: Acids, Bases, & Salts *KEY* Unit Vocabulary: Amphoteric Arrhenius acid Arrhenius base Bronsted-Lowry
More informationChem 112, Fall 05 Exam 3A
Before you begin, make sure that your exam has all 10 pages. There are 32 required problems (3 points each, unless noted otherwise) and two extra credit problems (3 points each). Stay focused on your exam.
More informationChapter 9: Acids, Bases, and Salts
Chapter 9: Acids, Bases, and Salts 1 ARRHENIUS ACID An Arrhenius acid is any substance that provides hydrogen ions, H +, when dissolved in water. ARRHENIUS BASE An Arrhenius base is any substance that
More informationPart One: Pure Solutions of Weak Acids, Bases (water plus a single electrolyte solute)
CHAPTER 16: ACID-BASE EQUILIBRIA Part One: Pure Solutions of Weak Acids, Bases (water plus a single electrolyte solute) A. Weak Monoprotic Acids. (Section 16.1) 1. Solution of Acetic Acid: 2. See Table
More informationVolume NaOH Delivered (ml)
Chemistry Spring 011 Exam 3: Chapters 8-10 Name 80 Points Complete five (5) of the following problems. Each problem is worth 16 points. CLEARLY mark the problems you do not want graded. You must show your
More informationUnit 10: Acids and Bases
Unit 10: Acids and Bases PROPERTIES OF ACIDS & BASES Properties of an Acid: a Tastes sour substance which dissociates (ionizes, breaks apart in solution) in water to form hydrogen ions Turns blue litmus
More informationSec Unit Review
hemistry 12 Sec 4.14 4.21 Sec 4.14 4.21 Unit Review Name ue ate 1. What colour would 1.0 M Hl be in an indicator mixture consisting of phenol red and thymolphthalein? red blue yellow colourless 2. uring
More informationChapter 16. Acid-Base Equilibria
Chapter 16 Acid-Base Equilibria Arrhenius Definition Acids produce hydrogen ions in aqueous solution. Bases produce hydroxide ions when dissolved in water. Limits to aqueous solutions. Only one kind of
More informationWe need to find the new concentrations of the species in this buffer system. Remember that we also DILUTED the solution by adding 5.0 ml of the HCl.
164 Take 100. ml of the previous buffer (0.05 M tris / 0.075 M tris-hcl), and add 5.0 ml of.10 M HCl. What is the ph of the mixture? The HCl reacts with the tris base, converting it to tris-hcl We need
More informationcm mol l -1 NaOH added to 50.0 cm 3 of 0.10 mol l -1 HCl
cm 3 0.10 mol l -1 NaOH added to 50.0 cm 3 of 0.10 mol l -1 HCl Acids have been described as substances that dissolve in water to form H + (aq) ions, whilst bases are substances that react with acids.
More information