An example of a strong acid solutiehm-5sd, ;omoon is nitric acid. Which statement is correct for this sol,s m -o5doe;hmution?

  Which of the following statements concerning acids and bases is nv9sk7 4hnei ddl+l wu5u47t9iot true?

  Which of the following is correct?g1o1dau )wda3

  Which statement about a strong acid and its conjugate base is co30 xe1s-kcr. 6t2vh3ddmmietrrect?

  Which of the following ex3(emp,cp b6 fzpressions for $K_w$ is correct?

  Which combination of acid and base should be reacted to obtain a basic a*sm7+k.9c fgy5x ocj salt?

  A reaction produces carbon dioxide gm.9i(byrjr e,w zez1g;:e* owas and a solution of water with a dissolved salt. What could be the r zw(9e ,yi;:o .egbe1wrzmrj *eactants?

  Which combination of acid and base will typically have the iej.0,un t4rblowest pH at the equival4.tnejir u0,bence point in a titration?

  In order to prepare a sol,:joz +o k sku84hohk05w0 mm9tq bf4wution 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 the ionic p t;x/7q+to(l8 htshp7-udygu roduct constant of water / 7dx7 thgp(+utyq8tuosl - ;hat ${25}^{\circ }$ 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 etqu1k bxct:; l+hanol is slowly converted to ethanoic acid. The \ce{p: x kq;+lutbc1H}pH of a bottle of wine changes from 6.5 to 4.5. The concentration of $[H{]}^{+}$ is?

  A molecule of HBr reacts with water to produce the charged molecn11fz6lbly )gk*yx 5y ule X. What is the L1l1bn6yyx lyk5*gf z) ewis structure of molecule X?

  Alkali solutions can be made by dissolving 3)r mk1pwfbowqtm yqm,1a *50a basic 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 nitric 3 cjp7*n0yb*8 bn wzvnacid $HN{O}_3$ 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 statements about acidsr*yx8f sau 4lkr+v2a 7 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 corre; ua 8ay1rcr+vct?
|.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 representscl4 93.x,:mq djfc2(g4nw skzpni,o b32x qxi $K_a$ for $C{H}_{3}COOH$?

  Given the following indicators and their behaviours, what will be thea +7rt n-duze- correct colours of a solution of ad-z+-r uen7t1.0 M 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 basebjo*rtke))zr2fu0or ux4n* ceut44: - ov *lpd 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 hydrog wap6 mlvd 2n30i*5nnpen 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 t *zjdpg:zwymxrn.cg7(u j7( :+vmk*3ipl o0$1.0mold{m}^{-3}$ solutions in order of increasing pH:
$NaOH,N{a}_{2}C{O}_3,NaCl$

  Which of the following reactions is not a neutralization reac4;oo*un0q7be a duj-;8 m ahlb+(fpa9 ml2ztgtion?

One example of an important buffer system is thepf,pxi+z, av 1u1ap6z $H_{2}C{O}_3/HC{O}_3^{-}$ 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 bet8skuy17nxy)mx --o ucween $N{H}_3$ 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 : c;:z ds*o5kjq ubu*h$0.001mold{m}^{-3}$ aqueous solution of KOH at 298K given that it ionizes completely?

Consider the following r t,2j 36dtwfskeaction:
$H_{2}S{O}_4(aq)+N{H}_3(aq)\rightleftharpoons HS{O}_4^{-}(aq)+N{H}_4^{+}(aq)$
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, whlif/; a9jusz4 en mixed with equal volumes at equal concentrations, form a buff/ ;ualf4sz9ji er 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 behavesyv1(pq.mx3 px as a strong acid when it reacts with 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 suitable for a titration between sodium hilc- 8-w5geqy2h5maxd4m wgf ia2d; 4 ydroxide and ethan4lw5 ymfqc; ad2x-g8 e4mihdg 5ai2-woic acid?

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

  Which statements are 2pj+00tdol hwq3h qr t6-3 ybccorrect?
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 actjgh x),;7j0 u -sj-13tanl f8e rcpcqid.
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 equivalence poq/-m/cj i tra2int of acid-base titrations is incorrect?r/qac- 2jt mi/

  Which of the following salts form basic solutions when dissolved in watl :iewuwlsb:l2 q67z s 2ar,,der?
I.$N{H}_{4}Cl$
II.$K_{2}C{O}_3$
III.$NaOOCC{H}_3$

  Which of the following combinm y)e*u:lv7h * 64zv xsv+wwm9mmvb(zations of $N{H}_3(aq)$ and HCl(aq) forms a buffer solution?

  The correct sequence in decream(n1v ir7xer wh1e1g3 sing order of pH for equimolar solutions is:

  Which of the three oxides of period 3 below will cause a chazmzi 1;jpx3f vk5 0)tenge in the pH of the solution when they react with water? j3 f;p5t) mxi0ze1zvk
I.$N{a}_{2}O$
II.$Si{O}_2$
III.$P_4{O}_{10}$

1. 1.Differentiate between a strong acid and a weak acid. fdg0lk( ql)ysy,h )m*
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 the rl o cd62 znn7r:9pnix gb,eq) l3-4jb$HN{O}_3$ 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 pHg z5cr9 mgw/3e is incorrect?

Ethanoic acid reacts with trimethylamine to produce a negatively cha7;m7l emjd2 ymrged ethanoate ion and another chly m7 edm7;mj2arged 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-bad 3p.k esvoe16v*p3 j 3v:sfwcse pairs are correctly matched with the salt formed from their rfpj v31wvs o.*3 6:sdkecve 3peaction?

This question is about the weak acid, carb jce0. xt0(0y;wprrj nonic 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 to determine the endpoint of a t :f2zk d 6hs(bqusdb+75j:a fu.kkl(witration.
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 containialdzde6laa g(r 18-lt.m3ki ht+i50s 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 concentr+d -di0lm k tl51ilz.ag8ae ia6 hr3t(ation $8.0\times {10}^{-4}mold{m}^{-3}$. 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 followinqn*5ajs7xve p(x ,nd. g equations is not an acid-base reaction according to the Bronxp esdaqx .nn5j7v, (*sted-Lowry theory?

Zinc(II) oxide reacts wi3fqkjktz;m3mn v3fk;0- s /ayth hydrochloric acid to produce an aqueous solution of zinc and chloride ion s;nvt33/k;jqk fak-0zfm3 y ms.
$ZnO(s)+2HCl(aq)\to Z{n}^{2+}(aq)+2C{l}^{-}(aq)+H_{2}O(I)$
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 h3* qmyks,fn cbv7v5f(ydrochloric acid in a conical flask, the products are water, positivfbf k73(5 y,cnvsvq*m e calcium ions and negative chloride ions.



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

  A bottle contains dilute ethanoic aci cq5ww 8:u,zhjd $C{H}_{3}COOH$ 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 rtg/vzm)ive +ceest 2:gw u2ig9;4 7g lequired to calculate the pH of a solution of a monoprotic weak acid? /t7 2v2:ei+g ge;z4sgvcgml 9t )i ewu
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 sulphuric acid v7l:m;u5u3jv 5src mx2i-0fe zmrh+band copper (II) ox2+xfsrjuu3c z b5-me5 ;vvm:l0 7himride.
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 or w+9o uyl3qz:ty eak.
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 wkjip9cv/6y r1 31pzt are two different theories of classifying acids a cv3zijrt9wk/116ppynd bases.
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 z 5* 4w4 pmtbd(;bk-wty9opgb commonly used to clean in houses, particularly glass such as windows. There are many pzo-wd( p bg wtm54*94;ytkbbsafety warnings on these products.
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 indicator, In, can be expreyeyt5nz l 0n1i gd9knib3) (7yssed using the equation itg)e9k(7 by15z3nnyidn0y l below
$In+H_{2}O\rightleftharpoons In{H}^{+}+O{H}^{-};K_c=35BlueYellowWhichofthebelowstatementsarecorrect?I.ThesolutionbecomesdarkerbluewiththeadditionofanacidII.ThesolutionisapalegreenatequilibriumIII.$K_c$ increases with the addition of an alkali

In the amino acid glycine, a hyd s3 vj+saes 3ozati,k-z5iq+:rogen ion may be transferred from one part of the molecule i,z q3k ss3svj zaoie5:+-+atto 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.