An example of a strong acid solution is nitric acid. Which statementuq6:tfdf1 eb5 is correct for this solutifufb:1e d65tqon?

  Which of the following statements concernp1p r3gkc 1;3) eupfl :)aoadning acids and bases is not true?

  Which of the following is nx2r ;g2kb0yaj ua3)ccorrect?

  Which statement about a strong acid and its conjugate bawdc32o5.7klun* m cqp se is correct?

  Which of the following z jt6 d7s.-c4dv4cxzwot2q *d expressions for $K_w$ is correct?

  Which combination of acid and bac pbx ey,t,c/o0u dz (+6/i zn1apj*xfse should be reacted to obtain a basic salt?

  A reaction produces carbo7hrxq552v)jh)f2pz he qvh; an dioxide gas and a solution of water with a dissolved salt. What could be the reactan 5h2 7)fj;r5azqhv )v2q xhphets?

  Which combination of ++.(noj o5. nkfiy ksap,xt *xacid and base will typically have the lowest pH at the equivalence point in a titratioxsf5+,yj k.ointk( n.opa+ x*n?

  In order to prepare a solution i;mgmyix,si9 (pzi cf de m*m,7k*h //of $0.1mold{m}^{-3}$ with the highest pH, substance XX is dissolved in water. Substance X is

  Water dissociates partially and the value of k7(i e,sd** )mvfym kjthe ionic product constant of water atjsd7 vi *emfy,kk )m(* ${25}^{\circ }$ is $1.00\times {10}^{-14}$.
1.State an equation for the dissociation of water.
2.Calculate the pH of a $0.0100mold{m}^{-3}$ of lithium hydroxide at 298K.  
3.Explain whether a $0.0100mold{m}^{-3}$ solution of calcium hydroxide will have a higher or lower pH than a $0.0100mold{m}^{-3}$ solution of lithium hydroxide at the same temperature.  $mold{m}^{-3}$

  When wine is exposed to air, the ethanol is slocx*ch/0e 6m kwwly converted to ethanoic acid. The \ce{pH}pH of a bottle of*/xck mc0h w6e wine changes from 6.5 to 4.5. The concentration of $[H{]}^{+}$ is?

  A molecule of HBr reacts with water to produce the charged molecule X. Whatfi y4mw22puv 8 is the Lewis structure ofw8yuiv 2p2 mf4 molecule X?

  Alkali solutions can be made by dissolving a basaio7 zjuc-ttbl, 3w ,/ic substance in water.
1.Determine the concentration of a solution of NaOH made by carefully dissolving 5.00 g of NaOH in sufficient distilled water to make $250.0c{m}^3$ total solution in a volumetric flask.  $mold{m}^{-3}$
2.An indicator was added to the solution made in (a), and it turned red. Using section 22 (Section 18- 2025 syllabus) in the Data booklet, state a possible indicator used.
3.The temperature of a $50.0c{m}^3$ sample of the solution containing the indicator from (b) was found to be ${22.0}^{\circ }C$. Suggest with a reason, two possible observations if a slightly larger quantity of HCl was added and stirred.
Important note: The section numbers mentioned in the video solution are specific to the 2024 syllabus.
You can refer to the question stem to find the section numbers for the 2025 syllabus.

  An aqueous solution of nitrigvv(fhmbr nf*; aq* w yt 74h5:j1lz8ic acid $HN{O}_3$ has a pH of 4. How many moles of this acid are found in $1d{m}^3$ of the solution?

  Which one of the following st0yt,fmzwo(o. q(utd 5atements about acids is/are true?
|. Acids will neutralize bases to form salts
||. Acids produce solutions with pH greater than 7
|||.Acids ionize to form $H^{+}$ ions when dissolved in water

  What statements about indicators are 2 hjqssp.y(y 6correct?
|.Indicators are typically weak acids or weak bases
||.Indicators are different colours in acidic and alkaline conditions
|||.The midpoint of the colour change of an indicator occurs when [$HIn$] = [$I{n}^{-}$]

  A solution of $1.0mold{m}^{-3}$ HCl is diluted to $0.1mold{m}^{-3}$. Which statement is correct?

  Which expression repressl,clgur5q gpn0* 49htmfv 5- ents $K_a$ for $C{H}_{3}COOH$?

  Given the following indicators and their k2yq-m0 kc6hf behaviours, what will be the correct colours of a solution of 1.0 Mm qhk60fcy2k- KOH tested with each indicator?

Indicator	pH range	Colour change (Acid- alkali)
Methyl orange	3.1- 4.4	Red – Orange
Bromocresol green	3.8 - 5.4	Yellow - Blue
Phenolphthalein	8.3 - 10.0	Colourless - Pink

  What is the order of increasing acid strength basgev51 grv5ik 8ed on the $p{K}_a$ values below?

Acid	$p{K}_a$
$CC{I}_{3}COOH$	0.66
$HCOOH$	3.75
$C_6{H}_{5}OH$	9.99
$C{H}_{3}OH$	15.5

  The structure of the hqx s b0r d2o.5/fdvtl0rq j21lydrogen phosphate ion is shown.


How many $H^{+}$ ions can react with one hydrogen phosphate ion?^+ions can react with one hydrogen phosphate ion?

  Place the following 2x ze/wd.+sqap p:eu*$1.0mold{m}^{-3}$ solutions in order of increasing pH:
$NaOH,N{a}_{2}C{O}_3,NaCl$

  Which of the following reactions is not a neutjpk9qw f7*ff+b5r ay* ralization reaction?

One example of an importa: - oxknbkd1blb+ (ts*:;pe 4 po2nbkpnt buffer system is the $H_{2}C{O}_3/HC{O}_3^{-}$ buffer in our blood.
1. 1.Define buffer solution.
2.Using relevant equations, describe how the $H_{2}C{O}_3/HC{O}_3^{-}$ buffer works.
A student has solutions of $0.5mold{m}^{-3}$ $NaOH,HCl,H_{2}C{O}_{3}andNaHC{O}_3$.
2.State two ways the $H_{2}C{O}_3/HC{O}_3^{-}$buffer can be made from these solutions.

  The reversible reaction betweenpngw9j 7g 79z ;ljhpq+ oao:f7 $N{H}_3$ and $H_{2}S{O}_4$ is:
$N{H}_3+H_{2}S{O}_4\rightleftharpoons N{H}_4^{+}+HS{O}_4^{-}$
Which compounds act as bases in the forward and backward reactions?

  What is the pH of a xswe(qbgrh n 4zq953b+3jof9$0.001mold{m}^{-3}$ aqueous solution of KOH at 298K given that it ionizes completely?

Consider the following reh 7j7a 3ab6crija f,/daction:
$H_{2}S{O}_4(aq)+N{H}_3(aq)\rightleftharpoons HS{O}_4^{-}(aq)+N{H}_4^{+}(aq)$
1. 1.Define a Brønsted-Lowry acid and a Lewis acid.
2.Deduce the two species acting as acids and their conjugate bases in the equation above.
2.Give an example of a species that is a Lewis acid but not a Brønsted-Lowry acid and explain why this is the case.

  Which of the following solutions, when frqoduk8 6bnw4/5: ejmixed with equal volumes at equal concentrations, form a buffer8j/f 5q4edknrb6:ou w solution?

  $10c{m}^3$ of an aqueous solution of HCl with pH 1.0 is mixed with $990c{m}^3$ of water. The pH of the formed solution is:

  $20c{m}^3$ of $0.100mold{m}^{-3}$ NaOH were slowly added to a $10c{m}^3$ sample of $0.100mold{m}^{-3}$ HCl,and the pH was measured throughout the addition.
The equation for the reaction is as follows: $NaOH(aq)+NCl(aq)\to NaCl(aq)+H_{2}O(l)$
The ionic product constant of water at ${25}^{\circ }C$ is $1.00\times {10}^{-14}$
1.Calculate the number of moles of NaOH remaining at the end of the addition.Mole ratio is 1:1 and NaOH is in excess by  $\times {10}^{-3}mol$
2.Calculate the concentration of $O{H}^{-}$ at the end of the addition.  $mold{m}^{-3}$
3.Using your value for $[O{H}^{-}]$ in (b), calculate the pH of the solution at the end of the addition.  

  Concentrated sulfuric acid behaves as a strong acid when it reacts witiu*zjp+d(( lu9z: e abh water:
$H_{2}S{O}_4(aq)\to H^{+}(aq)+HS{O}_4^{-}(aq)$
$HS{O}_4^{-}\rightleftharpoons H^{+}(aq)+S{O}_4^{2-}(aq)$
Which of the following is (are) true for $1.0mold{m}^{-3}$ of sulfuric acid?
I.$[H^{+}]$ is high
II.$[S{O}_4^{2-}]$ is high
III.$[S{O}_4^{2-}]=[HS{O}_4^{-}]$

  Which indicator would be most suq)qoh-h2xs4tl; 8ea iitable for a titration between sodium hydroxide and ethanoic acih; -o)a8eqqh sxil 24td?

Indicator	pKa
Methyl orange	3.7
Bromocresol green	4.7
Bromothymol blue	7.0
Phenolphthalein	9.6

  Which statements are6-o+n zb ize+a correct?
I.$C{H}_{3}N{H}_2$ is a Lewis base
II.HOOCCOOH is a Bronsted-Lowry acid
III.$C{H}_3^{+}$ is a Lewis acid

  Methanoic acid HCOOH is a weak acidvardh0 k/9k* j.
1.State the formula of the conjugate base of HCOOH.
2.HCl is a strong acid and dissociates in water as shown below:
$HCl(aq)\to H^{+}(aq)+C{l}^{-}(aq)$
1.Suggest the pH of the solution formed when HCl dissolves in water.
2.Compare the relative strengths of the respective conjugate bases of HCOOH and HCl.\ce{pH}pH value less than  
3.$0.01mold{m}^{-3}$ of a given monoprotic acid HA has a pH of 3.
1. This acid is  ----待选择----weakstrong .
2.Compare the electrical conductivity of HA(aq) and $HN{O}_3(aq)$, giving a reason for your choice.

  Which statement about the equivalen v*jsgv-/ta, ipia,9f ce point of acid-base titrations is incorrect ai,-*a 9fpi, v/gtsvj?

  Which of the following salts form basic solutions when dissol 8lb q q)bt8wgaczo174ved in water?
I.$N{H}_{4}Cl$
II.$K_{2}C{O}_3$
III.$NaOOCC{H}_3$

  Which of the followim(*( 4w(5kp.cc 1fuswbainl o ng combinations of $N{H}_3(aq)$ and HCl(aq) forms a buffer solution?

  The correct sequence in decreasing order of pH for mhwg kb1o+:bcr d2 3/pequimolar solutions is:

  Which of the three oxides of period 3 be 4 y cfbzn23v)dkh;x1flow will cause a change in the pH of the solution when they xh)n 3 ;2b1ffyvcz4dkreact with water?
I.$N{a}_{2}O$
II.$Si{O}_2$
III.$P_4{O}_{10}$

1. 1.Differentiate betwod 0e.kcl2 zo,r hk2o9een a strong acid and a weak acid.
2.State a balanced equation for the reaction between KOH and $HN{O}_3$.
Measuring the pH can be useful when trying to differentiate between different solutions.
A student has three unlabelled bottles of white powders. They know that the bottles contain either $KOH,KOOCC{H}_{3}orHN{O}_3$.The student has access to a pH meter and distilled water.
2.Outline how the student can determine which powder is inside each of the three unlabelled bottles. Include equations where relevant.

  Four features of theuk(f, +7uobk4y+/v.; eqmwqg iewnxjj:;7sh $HN{O}_3$ molecule are labelled a-d.

Why is one mole of $HN{O}_3$ able to react with one mole of NaOH?

  Which of the following statements about pH is inc6txblu -/2ru yo060rqvo /i4ijg4xt yorrect?

Ethanoic acid reacts with trimethylamine to produce arw vojhk(52 in743 /zzdes :e0bo8sej negatively charged ethanoate ion an7hnbo8sid o2ez/jr 4ev:sj5 z(we 30kd another charged compound X.


1.Ethanoic acid and the ethanoate ion differ by one hydrogen ion. State the name given to a pair of molecules that differ in this way.
2.State why trimethylamine is categorised as a Brønsted-Lowry base.
3.Ethanoic acid can be represented as $C{H}_{3}COOH$. This formula provides a better description of the bonding in the molecule than the alternative formula $C{H}_{3}C{O}_{2}H$.
1.Suggest why it is better to represent the structure of ethanoic acid as $C{H}_{3}COOH$ than as $C{H}_{3}C{O}_{2}H$.
2.The formula of compound X is $(C{H}_3{)}_{3}N{H}^{+}$.Draw the structural formula of compound X.
4.Water can react with both ethanoic acid and trimethylamine.
1.The reaction of water with ethanoic acid produces an ethanoate ion and another charged compound Y. State the formula of compound Y.
2.State the property of water and trimethylamine that allows them both to react with Brønsted-Lowry acids.

  Which of the following acid-xl sf x*njg;19y6/nrur7 f5hjbase pairs are correctly matched with the salt formed from their reactionyr*fxx/jfn9 h7g;61njlr us 5?

This question is about the weak acid, rd0 84bnwjeg(7b d9kjq5l p1 ccarbonic acid $H_{2}C{O}_3(p{K}_{a1}=6.35)$.
1. 1.Determine the pH of a $0.175mold{m}^{-3}$ solution of carbonic acid.
2.State one assumption made in your answer to (a)(i).
Carbonic acid is a diprotic acid so can undergo two dissociations. The second dissociation has a $p{K}_{a2}$ of 10.33.
2. 1.State the equation for the second dissociation of carbonic acid.
2.Comment on the degree of dissociation for this second proton, based on the value of $p{K}_{a2}$.

  Indicators are used toh:l : 3bcxg-oov-9vwo determine the endpoint of a titration.
1.Using a relevant equation, explain how acid-base indicators work.
2. 1.Calculate the pH of a $1.0mold{m}^{-3}$ solution of KOH.pH=  
2.Calculate the pH of a $0.5mold{m}^{-3}$ solution of $HN{O}_3$.pH=  
3.Using section 22 (Section 18- 2025 Syllabus) of the data booklet, suggest a suitable acid-base indicator for a titration between the solutions in (b)(i) and (b)(ii).
4.On the following axis, sketch the titration curve for the titration between the solutions in (b)(i) and (b)(ii), starting with $10c{m}^3$ of $HN{O}_3$ solution in the flask, and titrating with KOH.

  Commercial vinegar containst2:b 4w4axu z(rrkq/hdk/6sw a small percentage of ethanoic acid. A student wishes to determine the concentration of ethanoic acid in vinegar. She titrates a solution of ethanoic acid against a standard solution of potassium hydroxide of z/srb2haqw(u4k: kw 6 tx4 dr/concentration $8.0\times {10}^{-4}mold{m}^{-3}$. The equation for the reaction is:
$C{H}_{3}COOH(aq)+KOH(aq)\to C{H}_{3}COOK(aq)+H_{2}O(I)$
A volume of $25.0c{m}^3$ of vinegar was diluted with distilled water and made up to a volume of $250.0c{m}^3$ in a volumetric flask. A burette was filled with the diluted solution.
$25.0c{m}^3$ of potassium hydroxide solution was added to a conical flask and three drops of phenolphthalein indicator added.
1.Ethanoic acid is considered a weak acid. Define the term ‘weak acid’.
2.The results of the titration are shown in the table below:

Trial	Volume of Titre$(c{m}^3)$
1	21.0
2	21.2
3	20.8

1.Using section 22 (Section 18- 2025 Syllabus) of the IB data booklet, identify the color at the endpoint.
2.Calculate the concentration of dilute ethanoic acid.  
3.Calculate the concentration of ethanoic acid in vinegar.  $\times {10}^{-4}mold{m}^{-3}$
Important note: The section numbers mentioned in the video solution are specific to the 2024 syllabus.
You can refer to the question stem to find the section numbers in the 2025 syllabus.

  Which of the followingi;o(6vy, gvso equations is not an acid-base reaction according to the Bronsted-Lowry theory?,(s i;ov6gyvo

Zinc(II) oxide reacts with hn /vo b*olnd4(ydrochloric acid to produce an aqueous solution of zinc and l *4/doo(n nbvchloride ions.
$ZnO(s)+2HCl(aq)\to Z{n}^{2+}(aq)+2C{l}^{-}(aq)+H_{2}O(I)$
1.HCl is described as an acid because it is a hydrogen ion donor. State the term used to describe acidity of this type
2.State the conjugate base of HCl in this reaction, giving a reason for your answer.
3.An aqueous solution of HCl does not contain molecules of HCl. Draw the structural formula of the positively charged molecule formed in the solution, including the positive charge.
4.Zinc(II) oxide is amphoteric.
1.Define the term amphoteric.
2.Suggest a reaction that could be performed to confirm that zinc oxide is amphoteric, giving your reasoning.
3.Explain why zinc(II) oxide is not amphiprotic.

$H_{2}O$ is an example of an amphiprotic species meaning it can act as either an acid or base.
1. 1.Draw the Lewis structure of $H_{2}O$.
2.Explain why $H_{2}O$ can act as both a Brønsted-Lowry acid and Brønsted-Lowry base.
3.Explain why $H_{2}O$ can act as a Lewis base.
2. 1.State an example of an acid-base reaction where $H_{2}O$ acts as a Brønsted-Lowry acid and another where $H_{2}O$ acts as a Brønsted-Lowry base.
2.State an example of a Lewis acid-base reaction that is not a Brønsted-Lowry acid-base reaction where $H_{2}O$ acts as a Lewis base.

  When powdered calcium oxide is added to dilute hydrochloric acid i 8e/p(zmitz8ac+yw ;yn a conical flask, the products are water, positiv8mw p;8t+/i( ez cyazye calcium ions and negative chloride ions.



Which species is the conjugate base of hydrochloric acid in this reaction?

  A bottle contains dilute ebw*0i e dw)0rz dhqqv4n40u.ss6:yhp thanoic acid $C{H}_{3}COOH$ of unknown concentration. To determine the concentration of the acid, a student titrates the acid against a standard solution of KOH according to the following equation:
$C{H}_{3}COOH(aq)+KOH(aq)\to C{H}_{3}COOK(aq)+H_{2}O(I)$
1.Calculate the mass of KOH that must be used to prepare $400.0c{m}^3$ of a $0.100mold{m}^{-3}KOH$ solution.n=  mol , m=  g
2.Calculate the pH of the $0.100mold{m}^{-3}KOH$ solution given that it ionizes completely in solution as shown in the following equation: $KOH(aq)\to K^{+}(aq)+O{H}^{-}(aq)$ pH=  
3.During the titration, the student finds that exactly $20.0c{m}^3$ of the KOH solution neutralizes exactly $25.0c{m}^3$ of the $C{H}_{3}COOH$ solution. Calculate the concentration of the $C{H}_{3}COOH$ solution.C=  $mold{m}^{-3}$

  Hydrogen sulfide,$H_{2}S$, is a weak acid with a $p{K}_a$ of 7.04.
1.1.State the acid dissociation constant expression for $H_{2}S$.
2.Calculate $K_a$ for $H_{2}S$.  $\times {10}^{-8}$
2.1.State the base dissociation constant expression for $H{S}^{-}$.
2.Calculate $K_b$ for $H{S}^{-}$ assuming a temperature of 298K.  $\times {10}^{-7}$
3.Using your answers to parts (a)(i) and (b)(i), derive the equation $K_w=K_a\times K_b$

  Which quantities are required to calculate+d4 j(izlhukh cx m 99.p+wps0 the pH of a solution of a monoprotic weak acid?jm+0 phuk swhc(d.px4+9l9zi
I.The $p{K}_a$ of the weak acid
II.The concentration of the solution
III.The value of $K_w$

1.State the complete balanced equation for the reaction between sv)d l(e74lfgng-7c : ip lhik6ulphuric acid and copperg477id l pciklg)nlhvf(: -6e (II) oxide.
2.State the complete balanced equation for the reaction between ethanoic acid and potassium carbonate.
3.Outline two ways to monitor the rate of reaction for reaction (b) above.

  Acids and bases can be classified as strong./n1n kn .ftzzbr93hn or weak.
1.Explain why ammonia,$N{H}_3$ in an aqueous solution, acts as a weak base, using an equation.
2.An experiment was carried out to determine the energy change during the following reaction:
$2N{H}_3(aq)+H_{2}S{O}_4(aq)\to (N{H}_4{)}_{2}S{O}_4(aq)$
Initial temperature of each solution =${21.4}^{\circ }C$
Final temperature of the mixture = ${23.8}^{\circ }C$
1.State with a reason whether the sign of the enthalpy change for this reaction is positive or negative.
2.Suggest with a reason whether the magnitude of the enthalpy change will be  ----待选择----greatersmaller  if aqueous ammonia is replaced with potassium hydroxide.
​

The Brønsted-Lowry and the Lewis theories are two different theories of classnop)sp1nlr( 2ifying acids and bases.p (2)lnonp r1s
1. 1.Distinguish between the Brønsted-Lowry theory and the Lewis theory.
2.Define incomplete octet.
Consider the dimerization of $AlC{l}_3$:
$2AlCl\to 3A{l}_{2}C{l}_6$
2. 1.Draw structural formulas to represent this reaction.
2.Explain how this is an acid-base reaction under the Lewis theory but not the Brønsted-Lowry theory.

  The pH of a $0.1mold{m}^{-3}$ solution of phenol is 5.0. What is the approximate $K_a$ of phenol?

  A student reacts a $15c{m}^3$ sample of $0.10mold{m}^{-3}$ methylamine,$C{H}_{3}N{H}_2(K_b=4.47\times {10}^{-4})$,with $10c{m}^3$ of $0.10mold{m}^{-3}HN{O}_3$.
1. 1.Calculate the initial number of moles of methylamine in the sample.$n(C{H}_{3}N{H}_2{)}_{initial}$ =   $\times {10}^{-3}$
2.Calculate the final number of moles of methylamine after the neutralization reaction.
2.Calculate the pOH of the final solution.pOH=  

Aqueous ammonia solutions are common(tsjw9)ql i- ny/3:xfmjd ( xbly used to clean in houses, particularly glass such as windows. There are many safety warnings on these products.xfl)j btq-/3myd9in( j(xw : s
1.Ammonia mixed in water forms ammonium hydroxide. State the equation for this process.
2.One concern is that ammonia solutions could mix with acidic cleaning products, such as drain cleaner with sulphuric acid.
1.Determine the balanced equation for ammonium hydroxide reacting with sulphuric acid.
2.Suggest a reason this reaction could be dangerous.

  The function of the acid-base indicaxb otjs09i9n nqn, wjo- s0::ntor, In, can be expressed using the equation bj0 9nb0nqtiw snoj,-s9 ox: :nelow
$In+H_{2}O\rightleftharpoons In{H}^{+}+O{H}^{-};K_c=35BlueYellowWhichofthebelowstatementsarecorrect?I.ThesolutionbecomesdarkerbluewiththeadditionofanacidII.ThesolutionisapalegreenatequilibriumIII.$K_c$ increases with the addition of an alkali

In the amino acid glycine, a hydrogen ion may be*d(k tx /felk/yl:np(2c.khj*tvix 3 transferred from one part of the molecutlet/v :k* xkk(.x*/hj2(d3 fncylp ile to another as shown.



In this reaction, glycine acts as both a Brønsted-Lowry acid and a Brønsted-Lowry base.
1.State the part of the glycine molecule that acts as a Brønsted-Lowry acid in the forward reaction, giving a reason for your answer.
2.In an aqueous solution of glycine, the transfer of the hydrogen ion may involve two reaction steps. The first reaction step is shown.


(i)By considering how a hydrogen ion forms from a hydrogen atom, explain why the hydrogen ion is often referred to as a proton.
(ii)Explain why $H^{+}$ is not an accurate representation of the cation formed in this reaction.
3.Amino acids such as glycine can be used to produce long molecules called peptides. The shape of the peptide molecule is determined by the types of intermolecular interactions present between the amino acid side chains, which have different structures. Part of a peptide molecule is shown, with the side chains highlighted in bold.


Suggest why acid-base reactions could alter the shape of this peptide chain.