An example of a strong acid solution is nitric acid. Which statement is correct az-qtbum00h zlq(h zl8ai2 b7)) sj1 kfor this soluta bhj lzq(08-a1 7 zq )tizm)0ubs2hlkion?

  Which of the following statements czoredoew8(:ovb*k ,4oncerning acids and bases is not true?

  Which of the following is correct?4*ijpf., o;zw:-hlh9(kf di4 cryika

  Which statement about a strongx4 , oojl jo3y7gry)s5t.ab3 p acid and its conjugate base is correct?

  Which of the following express;1gybge1wx 2tckta 4( ions for $K_w$ is correct?

  Which combination of rgaq2 /d)6 c++ m8bfxozkyq9qrs(vs) acid and base should be reacted to obtain a basic salt?

  A reaction produces carbon dioxide gas and a solution of water with a dissolved9b3r43a 3o fao0 ct.j6vjxttb salt. What could be the reavcara obotf t3 369t.xj34 jb0ctants?

  Which combination of acid and base will typicallyg1+gpv g-0ooh have the lowest pH at the equivalence point ing10vgg hoo +-p a titration?

  In order to prepare a soluc1w/rpwr1i9z s 6w u;btion 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 thea7t (y 1lzq9qf ionic product constant of water att1lfzqyaq9 7( ${25}^{\circ }$ 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 slowly converted to ethanoic acid.m7ygdrs6;mj3b/1 yrl Ths 6 ;mjg/d l1y7bryr3me \ce{pH}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 chargeqkq5;7nnn*cnl u 0,tpy6 1vml;:wb,,smcgw wd molecule X. What is the Lewis structurepl n;0vc7c , 6ks,wgm,wtnwl b; qm1uqn*5y:n of molecule X?

  Alkali solutions can be made by dissolving a basinn 7)p9s jd1ggc 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 nikx /l3j px;nlw 6e.1botric 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 statements,v3c wmye54qv ms.09pq ,cl up 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 a6upr2cgi* .qi8h yh;wre correct?
|.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 represen; tp:oczmy )0ec 36olj(e+laq ts $K_a$ for $C{H}_{3}COOH$?

  Given the following ink w)fg1t2beb s .oq4h+dicators and their behaviours, what will be the correct colours of a solution of 1.0 M KOH tested with eachtb 2g k 4)s.1f+boweqh 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 based oaih(:-rkea :sn 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 hydrogen phospp/wg 7dpa8;dpj,w d +g*fxvh +hate 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 vo03zx tlk(q. $1.0mold{m}^{-3}$ solutions in order of increasing pH:
$NaOH,N{a}_{2}C{O}_3,NaCl$

  Which of the following reactions is not ,z9jn.esv9h frudc 2)a neutralization reaction?

One example of an important buffer systbl 7igj7p3 0jhem 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 beb clc*o; c9ou*tween $N{H}_3$ 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 y7g2n qeyh fy02x gv59$0.001mold{m}^{-3}$ aqueous solution of KOH at 298K given that it ionizes completely?

Consider the following react eb l/ :b5j:md,ni1e nbifu3m1ion:
$H_{2}S{O}_4(aq)+N{H}_3(aq)\rightleftharpoons HS{O}_4^{-}(aq)+N{H}_4^{+}(aq)$
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 mixed with equal volu kx.h(5tc3w8 e9,u: r9 usl5omtxrw gqmes at equal concentrations, form a buffer 5u5wtsur h 8txwq oc(xrg.9e: mk 9,3lsolution?

  $10c{m}^3$ 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 with 3f8ugf )/ibowwater:
$H_{2}S{O}_4(aq)\to H^{+}(aq)+HS{O}_4^{-}(aq)$
$HS{O}_4^{-}\rightleftharpoons H^{+}(aq)+S{O}_4^{2-}(aq)$
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 betweenfk(j3au9ry ( (qpuzi sy (8l8y sodium hydroxide and ei( p( r9kql8 8zuy(u3 aj(yysfthanoic acid?

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

  Which statements are correct? hcxiz6 k+xzhab:r ex/ m)t: g4s /rp4.
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 acid.ep rk7gfw if+6ak+*v7
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 h/k * dw-)*w dg+0(mvhmzteuy equivalence point of acid-base titrations is incorrectdv+ m-kzu0yhde (ww/*tm* h)g?

  Which of the following *;w5gk,:lg 0u.ga9 kerwifu csalts form basic solutions when dissolved in water?
I.$N{H}_{4}Cl$
II.$K_{2}C{O}_3$
III.$NaOOCC{H}_3$

  Which of the following combinations5gst7. uah6p2 kk ,qyc of $N{H}_3(aq)$ and HCl(aq) forms a buffer solution?

  The correct sequence in decreasing order of pH for equimol-daf)lha1q e b3,8obxar solutions is:

  Which of the three oxides of period 3 below will cause a c*0ybor vvx0vjz x3 sz+b gj-0g -qh.z9hange in the pH of the solution when they react with z h- osvz9 03.zbg gxyj+00r-*jvvbqxwater?
I.$N{a}_{2}O$
II.$Si{O}_2$
III.$P_4{O}_{10}$

1. 1.Differentiate between a strong acid and a gp8ddv to,qc*n3l j/w emm.;, 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 the r/bcn co+c// zf 4 isv+be:wl1$HN{O}_3$ 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 ap i.e68kg )vw7 /zztkis incorrect?

Ethanoic acid reacts with trimethylamine to produce a negatively charger8w;q r k,p9lbd ethanoaqrpk;w8br 9l ,te ion and 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-bqc6q kbk 7+dy/ase pairs are correctly matched with the salt formed frodk+ kcy7/b6qqm their reaction?

This question is about the weak ac 45 u1mw ok+,tjnero ;i+tx2a:s7aza cid, carbonic 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 an.g+ ho .gbt2x-u3cj q 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 contains a small percentagv1fe 6m oyqhi40w vvr1z;z6. re of ethanoic acid. A student wishes to determine the concentration of ethanoic acid in vinegazy 6r mf 1;oqe0 vv6v1rzwi.h4r. She titrates a solution of ethanoic acid against a standard solution of potassium hydroxide of 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 following equations is not an acid-base reactioc*kjmq00lh945 n dlsen according to the Bronsted-Lowry thed0n*q m eh0jl4c 5ksl9ory?

Zinc(II) oxide reacts with hydrochloric acid tle cjo j.*lnm,ql q;qb)3- 5vyo produce an aqueous solution of zinc and coc v)ejq5b l.ql,nq *;jy-lm3 hloride 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 in a conical flf cqes3-/j2 wpask, the products are wfe 2 qp-s3wjc/ater, positive calcium ions and negative chloride ions.



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

  A bottle contains dilute etr2o 1 vpe2vw;dhanoic 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 q+ :c8dlv7dr ( 3fn*obkok9 3dhgg (uuto calculate the pH of a solution of a monoprotic h( o:8qu3fddo v u3ck( 7l9+*kggdnr bweak acid?
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 kqv8itam9e.) sulphuric acid and k tqv)e.am9 i8copper (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 ovc( 3i aetfeq;*f .(xg6huua+r 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 classifow .nxia bg wev49,a6i7u)szb5 r:p3 bying acids and bases. uzsx oe7)wb3aig4b rn.v b6ai :w,95p
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 commonly used to clean in houses, particularly )*/73jvrt4 qbbbdpa e glass such as windows. There are many safety warnings ontbq4d3pj r vb7ba/ e)* 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 indica*fo1 liysq 9cc.ub+)btor, In, can be expressed using the equation bec 9iu)1o qc+l. *bfysblow
$In+H_{2}O\rightleftharpoons In{H}^{+}+O{H}^{-};K_c=35BlueYellowWhichofthebelowstatementsarecorrect?I.ThesolutionbecomesdarkerbluewiththeadditionofanacidII.ThesolutionisapalegreenatequilibriumIII.$K_c$ increases with the addition of an alkali

In the amino acid glt 4aw ouwj5/d-ycine, a hydrogen ion may be transferred from one part of the molecule to anothe-t4du/a jow w5r 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.