Acid-Base Equilibrium - University Homepage
AcidBaseEquilAcid-Base EquilibriumSee AqueousIons in Chemistry 1110 online notes for review of acid-basefundamentals!Acid- Base Reaction in Aqueous Salt SolutionsRecall that use [ ] to mean “concentration of”Recall that we will use H and H3O interchangeably[H ][H ][H ] [OH-][OH-][OH-]neutralacid or acidicbase or basicNaming Acids ( below is review of some CHEM 1110 material )Binary acidsHydro ic acid(nonmetal root)CompoundHClhydrogen chlorideH2 Shydrogen sulfideHFhydrogen fluorideAqueous solutionHCl(aq) hydrochloric acidH2S(aq) hydrosulfuric acidHF(aq) hydrofluoric acidOxoacids .ic acid .ous acid(root)ate icite ousSO42H2SO4H2SO3HNO3HNO2Sulfatehydrogen sulfateHydrogen sulfitehydrogen nitratehydrogen nitritesulfuric acidsulfurous acidnitric acidnitrous acidIf prefix continue to use:HClO4HClOperchloric acidhypochlorous acid1
AcidBaseEquil2Acid SaltsName cation and anion (know combining ratio from charges)Use “bi” in place of hydrogen:HSO4-hydrogen sulfatebisulfateIf several hydrogens then:H3PO4H2PO3HPO32PO33-phosphoric aciddihydrogen phosphatehydrogen phosphatephosphateNaHCO3(Na , HCO3-)sodium bicarbonateAcids and Bases - DefinitionsApplications observed in lab:Acid turns litmus redBase turns litmus blueAcid Base ConceptsArrheniusAcidproduce H , H3O hydroniumBaseproduce OH- in waterhydroxideBronsted-Lowrydonate protonaccept protonLewisaccept electron pairdonate electron pair
AcidBaseEquilArrhenius Acids and Bases - ExamplesAcid increase concentration of hydronium ion H3O Base increase concentration of hydroxide OHAcidHCl (aq) H2OHCl (aq) or writeor writeBase HCl H3O (aq) Cl- (aq)H (aq) Cl- (aq)H Cl-Ca (OH)2 (s) Ca2 (aq) 2OH- (aq)NH3 (aq) H2O NH4 (aq) OH- (aq)Often combine acid to base or base to acid to neutralize the otherAcid base water saltHCl(aq) NaOH(aq) H2O(l) NaCl (aq) (stays as ions Na , Cl-)Bronsted-Lowry ExamplesAcid is a substance that can donate a protonBase is a substance that can accept a protonReaction involves transfer of proton from acid to baseAcid 1 HC2H3O2 (aq)acetic acidBase 2 Acid 2 H2 O H3 O Base 1 C2H3O2acetateConjugate acid base pairs (above):Acid 1 to Base 1 - acid that gives up proton becomes a baseBase 2 to Acid 1 - base that accepts proton becomes an acidEquilibrium lies more to left so H3O is stronger acid than acetic acid.Water can act as acid or base.Acid 1H2 O Base 2 NH3 Conjugate acid base pairs (above):Acid 1 to Base 1Base 2 to Acid 1Acid 2NH4 Base 1 OH-3
books/hillchem3/medialib/media portfolio/15.htmlNH4 is stronger acid than H2O (NH4 wants to give up H )OH- is stronger base than NH3 (OH- want to get H )When an acid gives up a proton it forms a base.When a base accepts a proton if forms an acid.HAacid H2 ObaseH3 O acid AbaseConjugate acid base pairs in blue and green.ExampleNH4 acidH2 O H3 O baseacid NH3baseLewis Acid-Base Reaction - Example (be aware of but we will not use much docs/212/rev/acidbase/lewis.htmLewis definition ( very general )Ag AcidClBase AgCl(s)
AcidBaseEquilDefinitionsMonoprotic- donate one proton (HCl, HC2H3O2)Polyprotic- can donate more than one protonH2SO4hydrogen sulfatediprotic sulfuric acidH3PO4hydrogen phosphate triprotic phosphoric acidH2SO4HSO4acid 1 H2 O H3 O H2 O H3 O base 1 acid 2 HSO4 SO42base 1Amphiprotic (or amphoteric) Ion or molecule than can accept or donate a proton.Such as water OH- H2O H3O Electrolytes – strong and weakElectrolytes form ions in solution (conduct electricity).Strong electrolytes completely ionizeWeak electrolytes partially ionizeHydrochloric acid (strong)HCl H2 OAcetic acid (weak)HC2H3O2 (aq) H3 O Cl- H2O (l) H3O (aq) C2H3O2- (aq)Acetic acid stays mostly in the molecular formand only small percent is in the ionic formHC2H3O2C 2 H3 O2 -5
AcidBaseEquil6Acid Equilibrium constant (weak acids)Incorrect Form:K [H3O ] [C2H3O2-][HC2H3O2] [H2O]Correct Form:K [H3O ] [C2H3O2-][HC2H3O2]Pure liquids (H2O) are not included in the equationDo not include H2O because it is a pure liquid.Normally write acid dissociation constant KaKa [H3O ] [C2H3O2-][HC2H3O2] [H ] [A-][HA]α degree of dissociatonfraction of molecule that is ionic form100 α percent ionizedIf α 0.25then25% ionized (H , A-) and 75% unionized (HA)ProblemsKa concentration1) Find Ka from concentrationsExample:At 25 C 0.100M acetic acid is 1.34% ionized. What is Ka?98.66% unionized, 1.34% ionizedKa [H ][HC2H3O2- ][HC2H3O2-][H ] [C2H3O2-] (0.0134) (0.1000) 1.34x10-3 M (concentration)[HC2H3O2-] (0.986) (0.1000) 9.866x10-2 M (concentration)Ka (1.34x10-3) (1.34 x10-3) 1.82x10-5(9.87x10-2)In these problems, don’t have to write units because concentration is always in M.
AcidBaseEquil2) Find concentration of species in solution from KaOf .10M HNO2 (nitrous acid)HNO2 H .10-xx Ka 4.5x10-4.NO2xConstant Ka [H ] [NO2-][HNO2]4.5x10-4 (x2) / (0.10 – x)Simple approach:If x is small (x 5/100), then you do not need to use the quadratic equationbecause you can assume (0.10 –x) 0.10 The variable x is so small that it willnot make much difference in subtraction.4.5 x10-5 x26.7 x10-3 x6.7% ionized and 93.3% unionizedExact Solution:x2 4.5 x10-4x – 4.5 x10-5 0Quadratic Equationax2 bx c 0Quadratic Formula for xx -b (b2 -4ac)2aSubstitute in for a, b, c -4.5 x10-4 ((4.5 x10-4)2 – 4 (1) (-4 x10-5)2 (1)-4 -4.5 x10 (2.03 x10-7 1.80 x10-4)2-4 ( -4.5 x10 1.34 x10-2 ) / 2 ( 1.30 x10-2 ) / 27
AcidBaseEquilx 6.5 x10-3Select positive root, discard negative one (not shown)x [H ] [NO2-] 6.5 x10-3 M[HNO2] 9.4 x10-2 M.0065.0935.100Percent Ionized(6.5 x10-3/ 0.1) x100 6.5% ionized93.5% unionizedSo to compare answers:approximate 6.7%exact6.5%Starts to be different above 5% but we will simplify math if possibleCommon calculator mistakeIf you want to enter this number 10-14 in calculator:do1E-14 which is 1x10-14NOT 10 E-14 which is the same as 10 x10-14calculator takes E-14 to mean 10 raised to power -14so103 is 1E310–4.5 is 1E-4.53.2x103 is 3.2E3However when you write numbers working problemsdo not use E in what you writeto put in calculator use 3.2E3but for human to read write 3.2x1038
AcidBaseEquilAcid StrengthHA (aq)AcidH3O (aq) Conjugate AcidH2O (l) Base A- (aq)Conjugate BaseWith equilibrium expressionAcid dissociation constant: Ka [H ] [A-][HA]Ka largeKa small(molecular)HClstronger acidweaker acidAcid StrengthStronger favors right favors leftConjugate BaseWeakerHCN WeakerStrongergoes to ionized formstays unionizedCl- does not want protonHCl H ClCN- wants proton HCN CNHCN OH- CN- H2OStrengths of Bronsted Acids and BasesHA (aq)Acid 1 H2O (l) Base 2H3O (aq)Acid 2 A- (aq)Base 1HCl stronger acid than H3O H2O stronger base than ClEquilibrium favors weaker acid and weaker basesince strong acid will give up hydrogen and go to conjugate weak baseThe stronger the acid the weaker the conjugate baseTables available to relative strengthsFor ExampleHCl stronger acid Cl- weak base (does not want proton)HCN weak acid CN- stronger base (does want proton)9
AcidBaseEquil 10Leveling EffectStrongest acid that can exist in water is H3O so HClO4, HCl, HBr, HCl, HNO3,H2SO4 and other strong acids go completely to H3O Have to go to other solvent to deterimine order of strong acidsIn H2O, strongest base is OHIn water, strong acids (know these 6 common strong acids)HCl (hydrochloric)HBr (hydrobromic),HI (hydroiodic)H2SO4 (sulfuric) only first ionization strong H HSO4–HNO3 (nitric)HClO4 (perchloric)All of above are stronger than H3O but all produce H or H3O in waterCan assume other acids you encounter are weak if not one of six above.Strong acids dissociate 100% to ionic form(no molecules of acid remain – all ions)Common strong bases (know these)LiOH NaOH KOH Ca(OH)2Sr(OH)2 Ba(OH)2If solvent reduces different reagents to the same strength it is the leveling effect.Water has leveling effect on bases stronger than OHNH2- H2O NH3 OHNH2- is a strong base but OH- is the strongest base that can exist in water.
AcidBaseEquil 11Ionization of WaterWater is a weak electrolyteH2 O H2 O hydroniumH3 O hydroxideOH-H2 O H OH- (aq) Bronsted LowryAcid: proton donorBase: proton acceptorWrite K for waterK [H ] [OH-][H2O]where Kwor Kw [H ] [OH-]is the ionization constant for water atKw 1.0 x10-14 [H ] [OH-]at 25 oCneutral solution[H ] [OH-]acidic solution[H ] [OH-]basic solution[H ] [OH-]Example problems given H find OHInGiven 0.020 M HCl solutionFind [H ] ? , [OH-] ?HCl H Initial .0200Final 0.020Cl0.020Strong electrolyte, contribution of neutral water is negligible[H ] .020[OH-] 1.0 x10-14 1.0 x10-14 5.0 x10-13[H ]0.2 x10-1[OH-] 5.0 x10-1340 billion H for each OH- ion50 water molecules for each H 2000 billion water molecules for each OH- ion
AcidBaseEquil 12pH and pOHnegative log of hydrogen ion concentration, convenient way to representconcentration of H ionin these cases p means – log oflog is common or base 10 logarithm log (100) 2.00pH -log [H ]pH141040or equivalent to [H ] 10 –pH[H ]10-1410-1010-4100 1[OH-]10010-410-1010-14basic, alkaline pH 7acidic pH 7pOH -log [OH-] or equivalent to [OH–] 10 –pOH[H ] [OH-] 10-14log [H ] log [OH-] -14pH pOH 14[H ] [OH-] 1.0 x10-14Connections using above equationspH [H ] [OH-] pOH pHSummary of Key Equations for pHpH -log [H ]andpOH -log [OH-]and [OH–] 10 –pOHpH pOH 14[H ] [OH-] 1.0 x10-14[H ] 10 –pH
AcidBaseEquil 13Example pH and pOH problems1. Given [H ] Find pH2. Given pOH Find [H ]Example 1Given 0.020 M H , Find pHpH -log [H ] -log (0.020) -log (2.0 x10-2) - [log 2.0 log 10-2] - [ 0.301 -2.00 ]pH 1.699 1.702 significant figures (remember pH is a logarithm)Example 2Given pOH 4.40 Find [H ]pH 14 – pOH 14 - 4.40 9.60pH -log [H ] [H ] 10-pHantilog (pH)[H ] 10-9.60 10-10 x100.40 2.5 x10-10antilog (0.40) 2.5Logarithms and significant figures:Form of logarithm such as 1.70 is characteristic.mantissaIn 1.70 the characteristic is the 1 which only holds the decimal place andthe mantissa is the .70 the numbers after the decimal place.Only the mantissa .70 is counted as sig figs100.21 1.622 sig fig if logarithm1.2112.21 all 2 sig figs0.21
AcidBaseEquil 14Make sure on Calculator you are familiar with needed operations10xor yxor logor inv loglog is base 10common logarithm log (254) 2.405ln is base e (e 2.71828.) natural logarithmln (254) 5.537Remember pH and POH use common logarithms (log)Common calculator mistake1x10-14 is 1E-14 not 10E-14 which is 10 x10-14
AcidBaseEquil 15Indicators and EquilibriumMeasure pH with pH meter where response of meterdepends on [H ] concentrationMore qualitative is the use of indicatorsIndicator- organic compounds whose color depends on [H ] concentration ofsolutionlitmuslitmusredpH 5HIn litmus moleculepurple pH 5–8blue pH 8In- litmus ionHIn RedH Inblueincrease H acid then shift to left side (turns red)add OH- which decreases H then shift to right side (turns blue)Litmus has Ka value 10-7 [H ] [In-][HIn]so10-7 [In-] 1Requires 100x more HIn than In- to appear red-510[HIn] 10010-7 [In-] 1010-8 [HIn] 1Requires 10x more In- than HIn to appear blueDemo: Bromocreosol green indicatorHIn greenH Inblueadd acid H then shifts to left and turns greenadd base OH- removes H then shifts to right and turns blue
AcidBaseEquil 16Base EquilibriumKa Kb KwKb [HA] [OH-][A-]A- H2O HAKa [H ] [A-][HA]HA H OH- A-Ka Kb [H ] [A-] [HA] [OH-][HA][A-]Ka Kb [H ] [OH-] Kwand since Kw 1.0x10-14 thenKa Kb 1.0 x10-14example for HCN and CN–Ka (HCN) 4.9 x10-10Kb (CN-) 2.04 x10-5and Ka Kb 1.0 x10-14Ka KbpKa pKbWhat is the pH if concentration of ion and acid are equal?Ka [H ] [C2H3O2-] / [HC2H3O2]if [C2H3O2-] [HC2H3O2] thenKa [H ]Ka available Table in textbookso can define pKa - log KaandpKb - log KbSopH pKa if [acid] [conjugate base ion] one way to make buffer[ H2CO3] [HCO3-]pH will begin to change only if too much acid or base addedif [acid] [ion] 1.00 M thenAdd 0.01 mol of strong acid or base in 1L of solution with buffer to begin tochange pH of buffer solution
AcidBaseEquil 17pOH pKb if [base] [ conjugate acid ion ][NH3] [NH4 ]BuffersA solution that has a constant pH when small amounts of acid or base are addedA solution that resists changes in pHType of bufferacidic, low pHbasic, high pHneed equal concentrationweak acid and salt with common anionweak base and salt with common cationAcid buffer:HC2H3O2NaC2H3O2acetic acidH C2H3O2sodium acetate Na C2H3O2-HC2H3O2 H 1.0M1.8 x10-5 M remove H (shift to replenishadded H (shift to use up)C2H3O21.0MKa 1.8 x10-5Basic buffer:add equal amounts ofNH3ammoniumNH4 andNH4Clammonium chloride NH4 andNH3 H2O NH4 0.100.10remove OH- (shift to replace)added OH- (shift to remove)Ka (NH4 ) 5.56 x10-10pH pKaOH1.8 x10-5pH 9.25OHClKb 1.8 x10-5
AcidBaseEquil 18Example Buffer:Acetic acid and acetate bufferKa 1.82 x10-5pH 4.740Equal amounts pH pKaHC2H3O2 H C2H3O21.001.82 x10-51.00 mol/LWhat is pH after OH- is added to bring [ OH- ] 0.10Ka [H ] [C2H3O2-][HC2H3O2]1.82 x10-5 [H ] [A-] / [HA] [H ] [1.1] / [0.90 ]Initial [H ] 1.82 x10-5 and pH 4.740pH (No buff) OH- added HC2H3O2 H 1.00110.0010.999120.010.990130.10.90Ka [H ] (1.1)(0.9)1.82 x10-5 [H ] [1.1][0.9][H ] 1.49 x10-5pH -log [H ] -log (1.49 x10-5)pH 4.83Review alkaline (basic) or acid buffer if1/1 ratio then pH pKb or pH pKaWhat if ratio other than 1/1 used what will pH be? C2H3O21.001.0011.011.1pH ( buffer)4.7404.744.754.83
AcidBaseEquil 19Buffer if ratio other than 1/1 usedHenderson Haselbalch EquationFormal way to answer: What if ratio other than 1/1 used what will pH be?Or can just figure it out from equilibrium expressionpH pKa log [A-][HA]Ka [H ] [A-][HA]HA H A-[H ] (Ka) [HA][A-]log [H ] log Ka log [HA][A-]pH pKa log [A-][HA]Range of ratios 1/10 to 10/1log (1/10) -1 and log (10/1) 1pH pKa 1Can select range if not too far from pKaBuffer:HC2H3O2 1.00H C2H3O21.00 mol/LKa 1.82 x10-5Example add NaOH (aq) so OH- base neutralizes some of acid: if new conc:0.901.10Ka [H ] [C2H3O2-][HC2H3O2][H ] Ka [HC2H3O2][C2H3O2-][H ] (1.82 x10-5) (0.9/ 1.1) 1.49 x10-5pH 4.83
AcidBaseEquil 20No Buffer:for buffer above change from 4.74 4.83if enough OH- to make 0.10 M OHbut compare to 0.10 M NaOH with no bufferpOH -log [OH-] -log (0.10) 1 pH 13pH change from 7 13
AcidBaseEquil 21Buffer – another exampleCyanic acid- cyanate buffer to set pH 3.5What concentrations?HOCN H OCNKa 1.2 x10-4 [H ] [OCN-][HOCN]With Henderson- Haselbalch Eq.:pH pKa log [OCN-][HOCN]3.50 3.92 log x-0.42 log x10-0.42 0.38 [OCN-][HOCN][OCN-] 0.38 M[HOCN] 1.00MWithout Henderson- Haselbalch Eq.:10-pH [H ] 10-3.5 3.16 x10-4or pH 3.5Ka [H ] [OCN-][HOCN]Ka 1.2 x10-4 [OCN-][H ] 3.16 x10-4 [HOCN] 0.38[OCN-] / [HOCN] 0.38 socould have [OCN-] 0.38 Mand [HOCN] 1.00M
AcidBaseEquil 22Mixing (cation) (anion) ions in water and effect1. Neither cation or anion acts as acid or base.Cation of strong baseLi , K , Na , Ba2 , Sr2 Anion of strong acidCl-, NO3-, SO42Results of Mixing cation and anion: Neutral2. Cation is acidNH4 Anion is weak base. Cl-, NO3Results of Mixing cation and anion: Acidic3. Cation does not act as acid. Na , Na ,K Anion acts as base.CN , C2H3O2 , CO32Results of Mixing cation and anion: Basic4. Cation acts as acid. 1) NH4 2) NH4 Anion acts as base. 1) C2H3O2 2) CO32Results of Mixing cation and anion (1) : AcidicResults of Mixing cation and anion (2) : BasicIn case 4 have to know more information about acid and base such as Ka and Kbvalues. Ka and Kb are acid dissociation constant and base dissociation constant.
AcidBaseEquil 23Chemical Analysis and TitrationsRefer to lab work of acid/ baseUse reaction to determine amountsFamiliar with terminology of titrationsAnalyte substance whose concentration is being determinedTitrant added from buretBuretIndicator endpoint etc.Acid res?imgurl Titr01.gif&imgrefurl tr.html&h 640&w 480&sz 187&tbnid V7NZN4ynP3mWM:&tbnh 137&tbnw 103&hl en&start 2&prev 1%26sa%3DG
AcidBaseEquil 24Acid Base Titrations1) Strong acid titrated with strong base35 mL 0.1M HCl (analyte)pH -log [H ]pH 1.00add 0.1 M NaOH(aq) (titrant) to acid solution that has few drops of indicator in itAt equivalence point (35mL of base in example below) all the acid is neutralized.Equal moles of base (OH-) have been added to cancel the original (H ). pH isnow 7.0NA V A NB V BorNote: N normalitynAMAVA nBMBVB (1) (.10 M) (0.35 L) (1) (0.10 M) (0.035 -strong-acid-35ml.gif
AcidBaseEquil 252) Titrate weak acid with strong baseSuppose 50.0 mL of HC2H3O2 0.10 MKa 1.8 x10-5 [H ][A-][HA]Initial pH1.8 x10-5 x2/ .11.8 x10-6 x21.34 x10-3 [H ]pH ect19.htm
AcidBaseEquil em3/medialib/media portfolio/15.htmlpH begins above 1 because acid is only partially ionizedNote that at equivalence point pH 7 since C2H3O2- is anion of weak acidC2H3O2- H2 O At equivalence point:100% C2H3O2-, 0% HC2H3O2At 1/2 equivalence point:50% C2H3O2-, 50% HC2H3O2Since Ka [H ] [C2H3O2-][HC2H3O2]HC2H3O2 OHBase
AcidBaseEquil 27Structures of Hydroxy CompoundsNaOH is base andHOClis acidWhy different?*Low electronegativity tends to donate electrons to form positive speciesNa and ew/bp/ch11/acidbaseframe.html*High electronegativity tends to have a strong attraction for electrons so itremoves electrons giving negative OCl- and H bp/ch11/acidbaseframe.htmlMore oxygens means stronger. The acid oxygen atom helps to support xy compounds:Metals low electronegativity yields OH- baseNonmetals or metals with high oxidation numbers and high electronegativitiesyield H in water. Chromic acid H2CrO4 where Cr–OH
AcidBaseEquil 28Strengths and Structure of Acids* Binary acidsIn periodic table, across the table going right and down goes towards strongerbinary.In period, increasing strength goes to the right on table because higherelectronegativity so withdraws electrons more and thus release proton.Example:N O NH3H2 ObaseneutralFHFacidIn group, larger size as you go down a group because large electron cloud allowselectrons to be more easily removed.Example acid strength:HF HCl HBr HIWeakStrongacidacidsSize dominates when going down a group.* OxoacidsGeneral Form:a bH-O-ZIf you go up the periodic table and across to the right then you will go towardsstronger oxoacids. (up group, right across period)Example:NaOH HOH HOClIf Z metal with low electronegativity (Na) then pair b belong to O and acts as baseOH-.If Z nonmetal then pair b is covalent bond and Z will tend to help reduce electrondensity even though O is electronegative.
AcidBaseEquil 29Higher electronegativity of Z the easier protons are lostHOI HOBr HOClStronger acidElectronegativityIf Oxygen around Z then they help to withdraw charge from the H-O bondMore oxygens then stronger the substance is as an acidOxygens not OH(HO)mZOnn0123very weak acidweak acidstronger acidvery strong acidHOClHOClOHOClO2HOClO3HONOHONO2Remember not all hydrogens come off*Ethanol not acidic C2H6O no H come
Acid 1 to Base 1 - acid that gives up proton becomes a base Base 2 to Acid 1 - base that accepts proton becomes an acid Equilibrium lies more to left so H 3O is stronger acid than acetic acid. Water can act as acid or base. Acid 1 Base 2 Acid 2 Base 1 H 2O NH 3 NH 4 OH-
Drill: Identify the B-L acid and base in each of the following. Circle any amphoteric species acid acid base base Note: In both examples, water behaved as an acid or a base. A species that can act as an acid or a base is called amphoteric. Bronsted-Lowry (B-L) Theory – Cont. acid base 1) HNO 3
In this experiment an acid-base titration will be used to determine the molar concentration of a sodium hydroxide (NaOH) solution. Acid-base titrations are also called neutralization titrations because the acid reacts with the base to produce salt and water. During an acid-base titration, there is a point when the number of moles of acid (H ions)
Acid-bases occur as conjugate acid-base pairs. CH 3 COOH and CH 3 COO-are a pair. H 2 O and H 3 O are a pair. The conjugate base of an acid is the base that is formed when the acid has donated a hydrogen ion. The conjugate acid of a base is the acid that forms when base accepts a hydrogen ion. Example 2 Which are Br Ø nsted-Lowry acids and .
As in the weak acid-strong base titration, there are three major differences between this curve (in blue) and a strong base-strong acid one (in black): (Note that the strong base-strong acid titration curve is identical to the strong acid-strong base titration, but flipped vertically.) 1- The weak-acid solution has a lower initial pH.
Acid-Base Accounting: What is it? Acid-Base Accounting (ABA) is the balance between the acid-production and acid-consumption properties of a mine-waste material. Minerals in waste material (mostly sulfides; mostly pyrite) react with water and oxygen to produce sulfuric acid. This acid is
CHAPTER 8: ACID/BASE EQUILIBRIUM Already mentioned acid-base reactions in Chapter 6 when discussing reaction types. One way to define acids and bases is using the Brønsted-Lowry definitions. A Brønsted-Lowry acid donates hydrogen ions; a Brønsted-
be hard or soft and also be either weak or strong. In a competition reaction between two bases for the same acid, one must consider both the relative strength of the bases, and the hard/soft nature of each base and the acid. ZnO 2LiC4 H9 Zn C 4 H9 Li2 O borderline acid hard base hard acid soft base borderline acid soft b
the billionaire’s list in March 2019, The Trussell Trust reported that its “food bank network distributed 1.6 million three-day emergency food supplies to people in crisis, a 19% increase on the previous year. More than half a million of these went to children.” 22. Conclusion . This report clearly shows that wealth inequality is dangerously high in the UK, and it has worsened since 2010 .
