Acids, bases and salts — IGCSE Chemistry (0620) questions by topic

Which row gives the colours observed when thymolphthalein and methyl orange are added separately to the named solution? solution colour with thymolphthalein colour with methyl…

A mixture of two substances, R and S, is heated gently. The damp red litmus paper turns blue. The apparatus is a test-tube held at an angle containing the solid mixture R and S,…

Which reactants are used to make the salt copper(II) sulfate? A dilute acid + alkali B dilute acid + metal carbonate C dilute acid + metal D dilute acid + non-metal oxide

Which row describes an aqueous solution for the pH shown? pH description --- --- --- A 1 has a very high alkalinity B 5 is neutral C 9 turns universal indicator yellow D 14…

Which parts of the Periodic Table contain elements that only form basic oxides? A Group I and Period 3 B Group I only C Group VIII and Period 3 D Group VIII only

A solution containing hydroxide ions, OH-(aq), is added to a solution containing hydrogen ions, H+(aq). An equation representing the reaction is shown. H+(aq) + OH-(aq) - H2O(l)…

Which compound is an acidic oxide? A barium oxide B carbon dioxide C copper(II) oxide D magnesium oxide

Which statement describes a hydrated salt? A It is an aqueous solution of a salt. B It is a solid salt that is chemically combined with water. C It is a solid salt that contains…

Two experiments involving acids R or S are done. - 0.10 mol of acid R completely dissolves in 500 cm³ of water. 0.0048 mol of acid R is dissociated in the solution. - 0.10 mol of…

Lead(II) sulfate is an insoluble salt. Which process is not used to prepare a pure sample of this salt? A. crystallisation B. drying C. filtration D. precipitation

The formulae of two hydrated salts are shown. - CuSO₄·xH₂O - CoCl₂·yH₂O What are the values of x and y? x y --- --- --- A 5 5 B 5 6 C 6 5 D 6 6

Which row describes the conditions used in the manufacture of sulfuric acid by the Contact process? catalyst pressure temperature --- --- --- --- A iron high high B iron low low C…

A farmer incorrectly adds two substances to the soil at the same time. They react together to form a gas which turns damp red litmus paper blue. What are the two substances? A a…

Which row shows the equations for the dissociation of hydrochloric acid and of ethanoic acid in aqueous solution? hydrochloric acid ethanoic acid --- --- --- A HCl(aq) - H^+(aq) +…

Which three oxides are all acidic? A CaO, NO2, SO2 B CaO, CO2, Na2O C CO2, NO2, SO2 D CO2, Na2O, SO2

Aqueous ammonia forms an equilibrium with water. NH3 + H2O <= NH4+ + OH- In this equilibrium, which particle acts as an acid and which particle acts as a base? acid base --- ---…

Which row identifies an acidic oxide, a basic oxide and an amphoteric oxide? acidic basic amphoteric --- --- --- --- A ZnO SO2 Al2O3 B SO2 Al2O3 Na2O C ZnO Al2O3 SO2 D SO2 Na2O…

This question is about ionic and covalent compounds. Complete the word equation to show the reaction between magnesium carbonate and nitric acid. magnesium carbonate + nitric acid…

This question is about sea water and the substances found in sea water. Table 2.1 shows the masses of some of the compounds formed when 500 cm^3 of sea water is evaporated:…

This question is about sea water and the substances found in sea water. Table 2.1 shows the masses of the compounds present when a 2000 cm^3 sample of sea water is evaporated.…

This question is about ionic compounds and simple molecular compounds. Complete the word equation to show the reaction between copper(II) carbonate and nitric acid. copper(II)…

A list of substances is shown. bauxite, calcium oxide, ethanol, graphite, methane, nitrogen, oxygen, propane, propene, sulfur dioxide Answer the questions using the list of…

This question is about compounds of sulfur. Sulfuric acid is manufactured in a four-stage process. stage 1: Sulfur dioxide is produced from ores containing sulfur. stage 2: Sulfur…

Lead(II) chloride, PbCl2, is an insoluble salt. Solid lead(II) chloride can be made by reacting aqueous sodium chloride with aqueous lead(II) nitrate. 2NaCl(aq) + Pb(NO3)2(aq) -…

Lead(II) chloride, PbCl2, is an insoluble salt. Solid lead(II) chloride can be made by reacting aqueous sodium chloride with aqueous lead(II) nitrate. 2NaCl(aq) + Pb(NO3)2(aq) -…

Which statement about sodium oxide or nitrogen dioxide is correct? A Nitrogen dioxide is a solid at room temperature. B Nitrogen dioxide is acidic. C Sodium oxide has a lower…

A titration method is used to prepare a pure soluble sulfate salt from dilute sulfuric acid. What is the other reagent? A copper(II) oxide B magnesium C sodium hydroxide D zinc…

Four different solutions are separately tested with blue litmus and with methyl orange. Each solution is known to be either acidic or alkaline (solution; result with blue litmus;…

Which statement about sulfur dioxide or calcium oxide is correct? A Calcium oxide is an acid. B Calcium oxide turns thymolphthalein yellow. C Sulfur dioxide is a base. D Sulfur…

Which substances can be used to make pure crystals of sodium sulfate? A potassium sulfate and sodium hydroxide B sodium carbonate and sulfuric acid C sodium nitrate and magnesium…

Which row shows the colours of litmus and methyl orange with solutions of acids or bases? (columns: solution; litmus; methyl orange) A acid; red; red B acid; blue; yellow C base;…

Aqueous sodium hydroxide is reacted with excess dilute hydrochloric acid. Which ion causes the resulting mixture to be acidic? A Na⁺ B H⁺ C OH⁻ D Cl⁻

Universal indicator is added to an aqueous solution of oxide X. The indicator changes colour from green to red. What is X? A MgO B CaO C K2O D NO2

Which rows identify two aqueous salts which react together to produce a precipitate? (salt 1; salt 2): 1 sodium sulfate; barium nitrate 2 sodium chloride; barium sulfate 3 barium…

Which equation represents a solution of ethanoic acid in water? A HCOOH(aq) ⇌ HCOO⁻(aq) + H⁺(aq) B HCOOH(aq) → HCOO⁻(aq) + H⁺(aq) C CH3COOH(aq) ⇌ CH3COO⁻(aq) + H⁺(aq) D…

Four statements about the reactions of oxides with dilute hydrochloric acid and with aqueous sodium hydroxide are listed: 1 Aluminium oxide reacts with both dilute hydrochloric…

What is the colour of thymolphthalein in dilute hydrochloric acid? A blue B red C yellow D colourless

Two acids, P and Q, with the same concentration and volume are reacted separately with the same mass of magnesium ribbon. The reactions produce the same total volume of hydrogen…

Which process is not used in the preparation of an insoluble salt? A filtration B washing C crystallisation D drying

Lead(II) iodide is formed as a precipitate in the reaction shown: Pb(NO3)2(aq) + 2NaI(aq) → PbI2(s) + 2NaNO3(aq) Which method is used to separate the lead(II) iodide from the…

What is used to identify the end-point of an acid-base titration? A balance B measuring cylinder C indicator D volumetric pipette

Lead(II) bromide, PbBr2, is an insoluble salt and is made by precipitation. Name two aqueous solutions that produce a precipitate of lead(II) bromide when they are mixed.

Barium sulfate, BaSO4, is an insoluble salt and is made by precipitation. Name two aqueous solutions that produce a precipitate of barium sulfate when they are mixed.

You are going to investigate the reaction between aqueous aluminium chloride and two aqueous solutions of sodium hydroxide, solution F and solution G. Solution F and solution G…

You are provided with one solid: solid K. Do the following tests on solid K, recording all of your observations at each stage. Tests on solid K (a) Transfer approximately half of…

A student investigates the reaction between aqueous aluminium chloride and two aqueous solutions of sodium hydroxide, solution F and solution G, which have different…

Which statements about dilute ethanoic acid are correct? 1 It has a pH of 8. 2 It is an organic compound. 3 It turns universal indicator orange-yellow. 4 It reacts with magnesium…

An aqueous solution of Z turns universal indicator paper purple. Which row identifies the colour of methyl orange and of thymolphthalein when they are added separately to an…

Which row describes the solubility of lead(II) chloride and lead(II) sulfate in water? lead(II) chloride lead(II) sulfate --- --- --- A soluble soluble B soluble insoluble C…

Four different groups of oxides are shown. 1 MgO FeO CuO 2 CaO SO2 TiO2 3 PbO CaO Cl2O 4 NO2 Br2O P2O5 Which statement about these groups of oxides is correct? A 1, 2 and 3…

Four steps in the preparation of a soluble salt from a dilute acid and a solid metal oxide are listed. 1 Warm the dilute acid. 2 Evaporate the solution to half of its volume and…

Compound M contains calcium. Two reactions of M are listed. - M reacts with dilute hydrochloric acid to form a salt and water only. - M reacts with aqueous ammonium chloride to…

The diagram shows one period of the Periodic Table: Li Be B C N O F Ne. Which two elements form acidic oxides? A beryllium and lithium B carbon and neon C carbon and nitrogen D…

A student tests four solutions with universal indicator. Which colour identifies the solution containing the greatest concentration of OH- ions? A red B yellow C green D blue

The following steps are done to prepare solid magnesium sulfate. 1 filtration 2 measurement of 20 cm3 of dilute sulfuric acid using a measuring cylinder 3 evaporation 4 addition…

Which row shows an advantage and a disadvantage for the stated apparatus used in a titration? apparatus advantage disadvantage --- --- --- --- A 25 cm3 volumetric pipette measures…

Which row identifies a basic oxide and describes an alkali? basic oxide description of an alkali --- --- --- A sodium oxide insoluble base B sodium oxide soluble base C sulfur…

Which indicators turn blue when added to aqueous ammonia? 1 litmus 2 thymolphthalein 3 universal indicator A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

The solubility of some salts is shown. chloride nitrate sulfate carbonate --- --- --- --- --- barium soluble soluble insoluble insoluble lead(II) insoluble soluble insoluble…

A scientist uses a titration to calculate the concentration of acid in a sample of lemon juice. A measured volume of aqueous lemon juice and a few drops of an indicator are added…

Which substance is a raw material used to manufacture sulfuric acid? A vanadium(V) oxide B sulfur C sulfur dioxide D sulfur trioxide

Which colours are seen when litmus and methyl orange are added to separate samples of aqueous sodium hydroxide? litmus methyl orange --- --- --- A blue orange B blue yellow C…

Information about the solubility in water of four oxides is shown. Which oxide, when added to water, gives a solution with a pH less than pH 7? name of oxide solubility in water…

Copper(II) sulfate is made when copper(II) carbonate reacts with dilute sulfuric acid. CuCO3 + H2SO4 - CuSO4 + H2O + CO2 Pure copper(II) sulfate crystals are obtained. Which…

Which row shows the difference between a weak acid and a strong acid? weak acid strong acid --- --- --- A fully dissociated partially dissociated B concentrated dilute C dilute…

Which substance turns methyl orange red? A aqueous ammonia B dilute hydrochloric acid C aqueous sodium hydroxide D distilled water

Which row describes zinc oxide and calcium oxide? zinc oxide calcium oxide --- --- --- A basic acidic B acidic basic C amphoteric acidic D amphoteric basic

A known volume and concentration of aqueous sodium hydroxide is titrated against dilute hydrochloric acid. The volume of dilute hydrochloric acid needed to exactly neutralise the…

Which statement about dilute hydrochloric acid is correct? A It is a strong acid as it fully dissociates. B It is a strong acid as it partially dissociates. C It is a weak acid as…

The equations for three reactions are shown. 1 Pb(NO3)2(aq) + 2KI(aq) - PbI2(s) + 2KNO3(aq) 2 2AgNO3(aq) + CuI2(aq) - Cu(NO3)2(aq) + 2AgI(s) 3 CuO(s) + H2SO4(aq) - CuSO4(aq) +…

This question is about acids, bases and salts. Crystals of potassium chloride can be made by reacting an acid with an alkali. Name the acid and the alkali used.

A list of chemical and physical processes A to H is shown: A combustion; B diffusion; C melting; D neutralisation; E photosynthesis; F reversible reaction; G roasting; H thermal…

Copper(II) sulfate has the formula CuSO4. Aqueous copper(II) sulfate is a blue solution. A sample of aqueous copper(II) sulfate is made by adding excess copper(II) oxide, CuO, to…

Silver bromide, AgBr, is made when aqueous silver ethanoate, CH3COOAg, is added to aqueous sodium bromide, NaBr. The equation is shown in equation 1: CH3COOAg + NaBr → CH3COONa +…

This question is about sulfuric acid, H2SO4. Dilute sulfuric acid and aqueous sodium hydroxide can be used to prepare sodium sulfate crystals using a method that involves…

Limes and lemons are citrus fruits which contain aqueous citric acid in their juice. Citric acid reacts with alkalis such as aqueous sodium hydroxide. Plan an investigation to…

Limes and lemons are citrus fruits which contain aqueous citric acid in their juice. Citric acid reacts with alkalis such as aqueous sodium hydroxide. Plan an investigation to…

Some symbol equations and word equations, A to J, are shown. A Fe³⁺ + 3OH⁻ → Fe(OH)₃ B H⁺ + OH⁻ → H₂O C ethane + chlorine → chloroethane + hydrogen chloride D C₁₂H₂₆ → C₈H₁₈ +…

Solid sodium hydroxide is a base which dissolves to form an aqueous solution, NaOH(aq). State what is meant by the term base.

A student investigates the reaction between aqueous ammonia and two different aqueous solutions of copper(II) sulfate labelled A and B (different concentrations). Experiment 1:…

Solid cobalt(II) oxide is a base which is insoluble in water. It reacts very slowly with cold dilute sulfuric acid to form a solution of cobalt(II) sulfate. Describe how to make…

Answer the following questions using only the substances from the list (ammonium nitrate, carbon monoxide, copper(II) chloride, ethane, ethene, litmus, methane, methyl orange,…

This question is about lead(II) chloride, PbCl2. A student prepares a sample of insoluble lead(II) chloride, PbCl2, by mixing aqueous solutions of two salts in a beaker. Identify…

This question is about sulfuric acid and salts that are made from sulfuric acid. Zinc reacts with dilute sulfuric acid. Aqueous zinc sulfate is one of the products. Powdered zinc…