ChemistryICSE Class 8 · Chapter 6

Chemical Reactions ICSE Class 8: Types, Reactivity Series, Heat Changes and Oxides

Updated 15 October 2026 · Fact-checked

ICSE Class 8 sorts chemical reactions into combination, decomposition, displacement and double displacement. A more reactive metal displaces a less reactive one from its salt solution, giving the reactivity series. Reactions can be exothermic or endothermic, and oxides are classed as basic (metal), acidic (non-metal), amphoteric (ZnO, PbO) or neutral.

What Chemical Reactions is about

A chemical reaction turns reactants into new products. The CISCE Class VIII curriculum asks you to:

recognise four types of reaction: combination, decomposition, displacement and double displacement;
use the reactivity series of metals: a metal that displaces another metal from its salt solution is more reactive;
tell exothermic reactions (heat given out, such as neutralisation of an acid by a base) from endothermic processes (heat taken in, such as dissolving ammonium chloride in water);
understand neutralisation;
know that heating metal carbonates, nitrates and sulphates gives oxides (heating limestone gives CaO; heating lead carbonate gives PbO), and that oxides also form when an element is heated in air;
classify oxides as acidic, basic, amphoteric or neutral.

The reactivity series (most reactive first): K, Na, Ca, Mg, Al, Zn, Fe, Pb, [H], Cu, Hg, Ag, Au.

Weightage: CISCE publishes no question paper, marking scheme or chapter weightage for Class VIII Chemistry: your school sets and marks the exam. Chemical Reactions sits in the Theme: Chemical Reactions theme of the CISCE Curriculum for Upper Primary Classes (VI-VIII).Source: CISCE Curriculum for Upper Primary Classes (VI-VIII), RDCD 2016

Key concepts

Combination and decomposition

Combination (synthesis): two or more substances combine to form one product. $A + B \to A B$ .
$2 M g + O_{2} \to 2 M g O$ ; $C a O + H_{2} O \to C a (O H)_{2}$ ; $F e + S \to F e S$ .
Decomposition: one substance breaks down into two or more simpler substances, usually by heat, light or electricity. $A B \to A + B$ .
Heat: $C a C O_{3} \to C a O + C O_{2}$ .
Electricity: $2 H_{2} O \to 2 H_{2} + O_{2}$ (electrolysis of acidified water).

Worked example

Classify: (i) $C a O + H_{2} O \to C a (O H)_{2}$ (ii) $C a C O_{3} \to C a O + C O_{2}$ on heating.

Try it first, then show the solutionSolution

(i) Two reactants form one product: combination.
(ii) One reactant breaks into two products on heating: (thermal) decomposition.

Answer: (i) Combination (ii) Decomposition

Displacement and the reactivity series

In a displacement reaction, a more reactive element pushes a less reactive one out of its compound: $A + B C \to A C + B$ .

$F e + C u S O_{4} \to F e S O_{4} + C u$ : iron displaces copper (blue solution turns green; brown copper forms), so iron is more reactive than copper.

$C u + 2 A g N O_{3} \to C u (N O_{3})_{2} + 2 A g$ : copper displaces silver.

If no change occurs (copper in iron sulphate solution), the metal is less reactive. Doing such experiments places metals in order: the reactivity series
K > Na > Ca > Mg > Al > Zn > Fe > Pb > [H] > Cu > Hg > Ag > Au.

Metals above hydrogen displace hydrogen from dilute acids: $M g + 2 H C l \to M g C l_{2} + H_{2}$ .

Worked example

Will zinc react with copper sulphate solution? Will copper react with zinc sulphate solution? Explain.

Try it first, then show the solutionSolution

Zinc is above copper in the reactivity series, so it displaces copper: $Z n + C u S O_{4} \to Z n S O_{4} + C u$ .
Copper is below zinc, so it cannot displace zinc: no reaction.

Answer: Yes; no

Double displacement and neutralisation

In double displacement, two compounds exchange partners: $A B + C D \to A D + C B$ .

Precipitation: an insoluble product separates as a solid. $B a C l_{2} + N a_{2} S O_{4} \to B a S O_{4} + 2 N a C l$ (white barium sulphate); $A g N O_{3} + N a C l \to A g C l + N a N O_{3}$ (white silver chloride).
Neutralisation: an acid reacts with a base to form a salt and water. $N a O H + H C l \to N a C l + H_{2} O$ . It is a double displacement reaction and it is exothermic.

Uses of neutralisation: an antacid for acidity in the stomach, lime for acidic soil, baking soda on an ant bite.

Worked example

Complete and classify: $N a O H + H C l \to$

Try it first, then show the solutionSolution

Base + acid → salt + water: $N a O H + H C l \to N a C l + H_{2} O$ .
The ions exchange partners: double displacement; acid + base: neutralisation.

Answer: NaCl + H₂O; neutralisation (double displacement)

Exothermic and endothermic changes

Exothermic: heat is given out; the surroundings get warmer. Examples: burning of fuels, respiration, neutralisation of an acid with a base, quicklime with water.
Endothermic: heat is taken in; the surroundings get cooler. Examples: dissolving ammonium chloride in water (the beaker feels cold), photosynthesis, decomposition of calcium carbonate by heating.

A simple test: touch the outside of the test tube. Warmer → exothermic; colder → endothermic.

Worked example

When ammonium chloride is dissolved in water, the temperature falls from 25 °C to 19 °C. Is the process exothermic or endothermic?

Try it first, then show the solutionSolution

The temperature fell by 6 °C: heat was taken in from the water.
So the process is endothermic.

Answer: Endothermic

Making oxides

By heating salts (thermal decomposition):

Carbonates give the metal oxide and carbon dioxide: limestone $C a C O_{3} \to C a O + C O_{2}$ ; lead carbonate $P b C O_{3} \to P b O + C O_{2}$ .
Nitrates give the metal oxide, brown nitrogen dioxide and oxygen: $2 P b (N O_{3})_{2} \to 2 P b O + 4 N O_{2} + O_{2}$ .
Sulphates of some metals, on strong heating, give the metal oxide and oxides of sulphur.

By heating an element in air (combination with oxygen): $2 M g + O_{2} \to 2 M g O$ ; $S + O_{2} \to S O_{2}$ ; $C + O_{2} \to C O_{2}$ .

Worked example

Name the products and write the equation when lead carbonate is heated.

Try it first, then show the solutionSolution

A carbonate gives the metal oxide and carbon dioxide.
$P b C O_{3} \to P b O + C O_{2}$ : lead(II) oxide and carbon dioxide.

Answer: PbO and CO₂

Classifying oxides

Type	Usually from	Behaviour	Examples
Basic	metals	react with acids to give salt + water; soluble ones turn red litmus blue	CaO, MgO, Na₂O, CuO
Acidic	non-metals	react with bases to give salt + water; soluble ones turn blue litmus red	CO₂, SO₂, SO₃
Amphoteric	some metals	react with both acids and bases	ZnO, PbO, Al₂O₃
Neutral	some non-metals	neither acidic nor basic	CO, H₂O, N₂O, NO

Amphoteric zinc oxide: $Z n O + 2 H C l \to Z n C l_{2} + H_{2} O$ and $Z n O + 2 N a O H \to N a_{2} Z n O_{2} + H_{2} O$ .

Worked example

Classify the oxides: SO₂, MgO, ZnO, CO. Give a reason for ZnO.

Try it first, then show the solutionSolution

SO₂: acidic (non-metal oxide). MgO: basic (metal oxide). CO: neutral.
ZnO reacts with both acids and bases, so it is amphoteric.

Answer: Acidic, basic, amphoteric, neutral

Chemistry in real life: Chemical Reactions

Each concept, met in an everyday situation. Read the situation, try the problem, then check the solution. The one-line hook is what to remember.

Neutralisation

Suppose a farmer's soil is too acidic for a crop.

What can be added, and what kind of reaction takes place?

Try it first, then show the solutionSolution

Add a base such as quicklime or slaked lime.
The base neutralises the acid in the soil, forming a salt and water: a neutralisation reaction.

Answer: Lime; neutralisation

Memory hook: Acid + base → salt + water.

Endothermic process

Imagine an instant cold pack for a sports injury that turns cold when you squeeze it, because a salt such as ammonium chloride dissolves in water inside.

Why does the pack feel cold?

Try it first, then show the solutionSolution

Dissolving ammonium chloride takes in heat from the surroundings.
Heat flows out of your skin into the pack, so it feels cold: an endothermic process.

Answer: Dissolving takes in heat (endothermic).

Memory hook: Endo = heat enters, so it feels cold.

Decomposition to an oxide

Suppose a lime kiln heats 250 kg of pure limestone strongly.

Name the products and find the mass of quicklime made (CaCO₃ = 100, CaO = 56).

Try it first, then show the solutionSolution

$C a C O_{3} \to C a O + C O_{2}$ : quicklime and carbon dioxide.
100 kg gives 56 kg of CaO, so 250 kg gives $2.5 \times 56 = 140$ kg.

Answer: 140 kg of quicklime (and CO₂)

Memory hook: Heating a carbonate leaves the oxide.

Topics in this chapter

Chemical Reactions formula sheet

Combination: $A + B \to A B$; One product.
Decomposition: $A B \to A + B$; By heat, light or electricity.
Displacement: $A + B C \to A C + B$; A more reactive than B.
Double displacement: $A B + C D \to A D + C B$; Includes precipitation and neutralisation.
Neutralisation: $acid + base \to salt + water$; Exothermic.
Limestone: $C a C O_{3} \to C a O + C O_{2}$; Thermal decomposition gives an oxide.

Chemical Reactions: diagrams to practise

Practise each one on paper: draw it from the checklist, then tick off every label.

Iron displacing copper

Show an experiment that proves iron is more reactive than copper.

Draw

A test tube of blue copper sulphate solution with a clean iron nail in it.
The same tube later: green solution and brown deposit on the nail.

Label

Copper sulphate solution (blue)
Iron nail
Iron sulphate solution (green)
Copper deposit (brown)

Watch out: Write the equation Fe + CuSO₄ → FeSO₄ + Cu below the diagram.

How the school exam asks Chemical Reactions

The question patterns to expect, and the method that works for each.

Question type	How it is asked	Method
Identify the type	Classify given equations as combination, decomposition, displacement or double displacement.	Count reactants and products and see what swaps.
Reactivity series	Will Cu displace Ag from AgNO₃? Arrange metals in order from experiments.	Higher in the series displaces lower.
Heat changes	Classify as exothermic or endothermic with a reason.	Heat given out (warmer) or taken in (colder).
Oxides by heating	Write equations for heating limestone, lead carbonate, lead nitrate.	Carbonate → oxide + CO₂; nitrate → oxide + NO₂ + O₂.
Classify oxides	Classify CO₂, Na₂O, ZnO, CO; explain amphoteric.	Metal → basic, non-metal → acidic; ZnO, PbO amphoteric; CO, N₂O neutral.

Tricks to remember Chemical Reactions

Short memory aids. Say each one aloud once, then use it on a question the same day.

Please Stop Calling Me A Zebra, Instead Learn How Copper Makes Silver Gold
K Na Ca Mg Al Zn Fe Pb H Cu Hg Ag Au: Potassium, Sodium, Calcium, Magnesium, Aluminium, Zinc, Iron, Lead, Hydrogen, Copper, Mercury, Silver, Gold.
Use it when: Reactivity series order.
Bully metal
A more reactive metal 'bullies' a weaker one out of its salt.
Use it when: Displacement.
Metal oxide basic, non-metal oxide acidic
Except the amphoteric pair ZnO and PbO, which go both ways.
Use it when: Classifying oxides.
Exo = exit
In exothermic reactions heat exits; in endothermic reactions heat enters.
Use it when: Heat changes.

Chemical Reactions: exam-level solved questions

Ordered from exam level to HOTS. Cover the solution, write your own, then compare step by step.

Example 1: Identify displacement · 1 mark · MCQExam level

Which is a displacement reaction?
(a) $C a C O_{3} \to C a O + C O_{2}$
(b) $Z n + C u S O_{4} \to Z n S O_{4} + C u$
(c) $2 M g + O_{2} \to 2 M g O$
(d) $N a O H + H C l \to N a C l + H_{2} O$

Try it first, then show the solutionSolution

In (b) zinc takes the place of copper in the salt.
(a) decomposition, (c) combination, (d) double displacement.

Answer: (b)

Example 2: Exothermic or endothermic · 2 marks · Short answerExam level

Classify as exothermic or endothermic: (i) neutralisation of hydrochloric acid by sodium hydroxide (ii) dissolving ammonium chloride in water.

Try it first, then show the solutionSolution

(i) Heat is given out; the solution warms: exothermic.
(ii) Heat is taken in; the solution cools: endothermic.

Answer: (i) Exothermic (ii) Endothermic

Example 3: Four types · 3 marks · Short answerExam level

Classify each reaction: (i) $F e + S \to F e S$ (ii) $2 H_{2} O \to 2 H_{2} + O_{2}$ (electricity) (iii) $A g N O_{3} + N a C l \to A g C l + N a N O_{3}$ .

Try it first, then show the solutionSolution

(i) Combination: two elements form one compound.
(ii) Decomposition by electricity (electrolysis).
(iii) Double displacement (precipitation of white silver chloride).

Answer: Combination; decomposition; double displacement

Example 4: Ordering metals · 3 marks · Short answerHarder exam level

Metal X displaces copper from copper sulphate solution but does not displace zinc from zinc sulphate solution. Copper displaces silver from silver nitrate. Arrange X, Cu, Zn and Ag in order of reactivity.

Try it first, then show the solutionSolution

X displaces Cu: X > Cu. X does not displace Zn: Zn > X.
Cu displaces Ag: Cu > Ag.
Order: Zn > X > Cu > Ag.

Answer: Zn > X > Cu > Ag (X could be iron)

Example 5: Heating salts · 3 marks · Short answerHarder exam level

Write balanced equations for heating (i) calcium carbonate (ii) lead nitrate. Name one observation in (ii).

Try it first, then show the solutionSolution

(i) $C a C O_{3} \to C a O + C O_{2}$ .
(ii) $2 P b (N O_{3})_{2} \to 2 P b O + 4 N O_{2} + O_{2}$ .
Brown fumes of nitrogen dioxide are seen.

Answer: As above

Example 6: Amphoteric oxide · 4 marks · Long answerHarder exam level

What is an amphoteric oxide? Show with equations that zinc oxide is amphoteric.

Try it first, then show the solutionSolution

An amphoteric oxide reacts with both acids and bases to form a salt and water.
With an acid: $Z n O + 2 H C l \to Z n C l_{2} + H_{2} O$ .
With a base: $Z n O + 2 N a O H \to N a_{2} Z n O_{2} + H_{2} O$ (sodium zincate).
So ZnO behaves as a base and as an acid: amphoteric.

Answer: As above

Example 7: Unknown metal powders · 4 marks · Long answerHOTS / competency

Three metals P, Q and R are tested. P reacts with dilute hydrochloric acid giving a gas; Q does not react with dilute acid; R displaces P from P's sulphate solution. (i) Arrange P, Q and R by reactivity. (ii) Name the gas and write a general equation for P (valency 2) with HCl. (iii) Could Q be magnesium?

Try it first, then show the solutionSolution

R displaces P, so R > P. P reacts with acid (above hydrogen) and Q does not (below hydrogen), so P > Q.
(i) R > P > Q.
(ii) Hydrogen: $P + 2 H C l \to P C l_{2} + H_{2}$ .
(iii) No: magnesium is above hydrogen and reacts readily with dilute acid; Q is below hydrogen (like copper).

Answer: (i) R > P > Q (ii) hydrogen (iii) no

Case-study practice (Section B style)

Read the situation, then answer every part. In a school exam set on the board pattern this is a 8-mark question split into 2 + 3 + 3 marks.

The school chemistry fair

Suppose students set up four tables: (A) a strip of zinc in copper sulphate solution; (B) dilute acid mixed with sodium hydroxide, with a thermometer; (C) ammonium chloride stirred into water, with a thermometer; (D) a sample of limestone heated strongly in a tube, with the gas bubbled through lime water.

(i) · 2 marks
Name the type of reaction at tables A and D, with equations.
Answer
Answer: A displacement; D decomposition
A: $Z n + C u S O_{4} \to Z n S O_{4} + C u$ (displacement). D: $C a C O_{3} \to C a O + C O_{2}$ (thermal decomposition).
(ii) · 3 marks
What happens to the thermometer readings at tables B and C, and why?
Answer
Answer: B rises; C falls
B: neutralisation gives out heat (exothermic), so the temperature rises. C: dissolving ammonium chloride takes in heat (endothermic), so it falls.
(iii) · 3 marks
At table D the lime water turns milky. Name the gas, write the equation for the milkiness, and classify the oxide formed in the tube.
Answer
Answer: CO₂; CaO is a basic oxide
Carbon dioxide: $C O_{2} + C a (O H)_{2} \to C a C O_{3} + H_{2} O$ (white calcium carbonate). The solid left, CaO, is a metal oxide: basic.

Where the marks are

How a typical answer is split into step marks. Show every step: a right final answer alone rarely earns full marks.

Define a displacement reaction with one example. (2 marks)

Step	Marks
A more reactive element displaces a less reactive element from its compound	1
$F e + C u S O_{4} \to F e S O_{4} + C u$	1

Classify the oxides CO₂, Na₂O and PbO, giving a reason for each. (3 marks)

Step	Marks
CO₂: acidic, a non-metal oxide that reacts with bases	1
Na₂O: basic, a metal oxide that reacts with acids	1
PbO: amphoteric, reacts with both acids and bases	1

Write balanced equations for: (i) heating lead carbonate (ii) magnesium burning in air (iii) neutralisation of sodium hydroxide by sulphuric acid. Classify (i) and (ii). (4 marks)

Step	Marks
(i) $P b C O_{3} \to P b O + C O_{2}$	1
(ii) $2 M g + O_{2} \to 2 M g O$	1
(iii) $2 N a O H + H_{2} S O_{4} \to N a_{2} S O_{4} + 2 H_{2} O$	1
(i) decomposition; (ii) combination	1

Where students lose marks in Chemical Reactions

The slips examiners see most often, and what to write instead.

Mistake: Expecting a less reactive metal to displace a more reactive one
Copper cannot displace iron or zinc from their salts.
Wrong working
$C u + F e S O_{4} \to C u S O_{4} + F e$
Right working
No reaction
Do this: Check the reactivity series before writing a displacement equation.
Usually costs: The whole equation.
Mistake: Calling every metal oxide basic
ZnO and PbO are amphoteric.
Do this: Learn the amphoteric pair.
Usually costs: 1 mark.
Mistake: Calling CO acidic
Carbon monoxide is a neutral oxide.
Do this: Neutral oxides: CO, H₂O, N₂O, NO.
Usually costs: 1 mark.
Mistake: Unbalanced nitrate equations
Nitrate decompositions need careful balancing.
Wrong working
$P b (N O_{3})_{2} \to P b O + N O_{2} + O_{2}$
Right working
$2 P b (N O_{3})_{2} \to 2 P b O + 4 N O_{2} + O_{2}$
Do this: Balance N first, then O.
Usually costs: 1 mark.
Mistake: Mixing up exothermic and endothermic
If the surroundings get colder, heat was taken in.
Do this: Warmer = exothermic; colder = endothermic.
Usually costs: 1 mark.

Practice questions on Chemical Reactions

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQExam level
Which oxide is amphoteric?
(a) CaO
(b) SO₂
(c) ZnO
(d) CO
Hint
Reacts with acids and bases.
Answer
(c)
Q2 · 1 mark · Very short answerExam level
Name the type of reaction: $2 M g + O_{2} \to 2 M g O$ .
Hint
One product.
Answer
Combination.
Q3 · 2 marks · Short answerExam level
Give one example each of an exothermic and an endothermic process.
Hint
Neutralisation; ammonium chloride.
Answer
Exothermic: neutralisation of an acid by a base. Endothermic: dissolving ammonium chloride in water.
Q4 · 2 marks · Short answerHarder exam level
Will copper displace silver from silver nitrate solution? Write the equation if it does.
Hint
Cu is above Ag.
Answer
Yes: $C u + 2 A g N O_{3} \to C u (N O_{3})_{2} + 2 A g$ .
Q5 · 1 mark · Assertion-reasonHarder exam level
Assertion (A): Iron displaces copper from copper sulphate solution.
Reason (R): Iron is more reactive than copper.
(a) (A) is true and (R) is false.
(b) (A) is false and (R) is true.
(c) Both (A) and (R) are true, and (R) is the correct explanation for (A).
(d) Both (A) and (R) are true, but (R) is not the correct explanation for (A).
Hint
Reactivity series.
Answer
(c)
Q6 · 2 marks · Short answerHarder exam level
Classify the reaction $B a C l_{2} + N a_{2} S O_{4} \to B a S O_{4} + 2 N a C l$ and state one observation.
Hint
Partners exchange.
Answer
Double displacement (precipitation); a white precipitate of barium sulphate forms.
Q7 · 2 marks · Short answerHarder exam level
Write the equation for heating zinc carbonate and classify the oxide formed.
Hint
Carbonate → oxide + CO₂.
Answer
$Z n C O_{3} \to Z n O + C O_{2}$ ; ZnO is amphoteric.
Q8 · 2 marks · Short answerHarder exam level
How much quicklime can be obtained from 50 kg of pure limestone? (CaCO₃ = 100, CaO = 56)
Hint
100 → 56.
Answer
28 kg.
Q9 · 3 marks · Short answerHarder exam level
Show by equations that lead(II) oxide is amphoteric.
Hint
Acid and base.
Answer
$P b O + 2 H N O_{3} \to P b (N O_{3})_{2} + H_{2} O$ and $P b O + 2 N a O H \to N a_{2} P b O_{2} + H_{2} O$ .
Q10 · 3 marks · Short answerHarder exam level
Sulphur burns in air. Write the equation, name the product, and state its nature and its effect on moist blue litmus.
Hint
Non-metal oxide.
Answer
$S + O_{2} \to S O_{2}$ , sulphur dioxide; an acidic oxide, it turns moist blue litmus red.
Q11 · 3 marks · Short answerHOTS / competency
An iron spoon is used to stir copper sulphate solution, and a brown layer appears on it. Explain with an equation. Can a copper vessel be used to store iron sulphate solution? Explain.
Hint
Which way does displacement go?
Answer
Iron displaces copper: $F e + C u S O_{4} \to F e S O_{4} + C u$ , so copper coats the spoon. A copper vessel would not react with iron sulphate, because copper is less reactive than iron, so copper can safely hold it.
Q12 · 3 marks · Short answerHOTS / competency
A solution warms from 24 °C to 31 °C when an acid is added to an alkali, and another cools from 24 °C to 18 °C when a salt is dissolved. Find the temperature change in each and classify the processes.
Hint
Up = exo, down = endo.
Answer
First: +7 °C, exothermic (neutralisation). Second: −6 °C, endothermic (dissolving, as with ammonium chloride).

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.Name the four types of reaction in this chapter.Show answer
Combination, decomposition, displacement, double displacement.
2.Which is more reactive: zinc or copper?Show answer
Zinc.
3.Products of neutralisation?Show answer
Salt and water.
4.Is neutralisation exothermic or endothermic?Show answer
Exothermic.
5.Is dissolving NH₄Cl in water exothermic or endothermic?Show answer
Endothermic.
6.Product of heating limestone?Show answer
Calcium oxide (and carbon dioxide).
7.Name two amphoteric oxides.Show answer
ZnO and PbO.
8.Name a neutral oxide.Show answer
Carbon monoxide (or water, N₂O).

Best order to study it

Learn the four types of reaction with one equation each.
Learn the reactivity series and practise displacement predictions.
Learn neutralisation and exothermic/endothermic examples.
Learn how oxides are formed by heating salts and elements.
Finish with the classification of oxides.

Quick revision checklist

The night before the exam: can you do each of these without looking?

Can you classify any given equation by type?
Can you recite the reactivity series?
Can you predict whether a displacement will happen?
Can you name one exothermic and one endothermic process?
Can you write equations for heating CaCO₃, PbCO₃ and Pb(NO₃)₂?
Can you classify oxides into four types?

Chemical Reactions: frequently asked questions

Why is hydrogen included in the reactivity series?

It is a reference point: metals above hydrogen can displace it from dilute acids; metals below cannot.

Is neutralisation a double displacement reaction?

Yes. The acid and the base exchange partners to form a salt and water.

Why does lime water turn milky with carbon dioxide?

Carbon dioxide reacts with calcium hydroxide to form insoluble white calcium carbonate.

Do all sulphates give oxides on heating?

Some metal sulphates decompose on strong heating to the metal oxide and oxides of sulphur; it needs much more heat than for most carbonates.

What is an amphoteric oxide?

An oxide that reacts with both acids and bases to form salt and water, such as zinc oxide and lead oxide.

Based on: CISCE Curriculum for Upper Primary Classes (VI-VIII), Science: Chemistry (Class VIII); CISCE RDCD: Curriculum Pre-School to Class VIII