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Chemistry Past Questions

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50 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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50 questions

Question 1 of 20 50 total questions

Question 11

waec 2025

Which of the following conditions are necessary for the preparation of alkanoates from alkanols and alkanoic acids?

AWater and NaOH

BConc. H\(_2\)SO\(_4\) and heat

CNaOH and heat

DWater and aqueous HCl

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Question 12

waec 2025

The percentage by mass of water in Na\(_2\)CO\(_3\).10H\(_2\)O is [ Na\(_2\)CO\(_3\).10H\(_2\)O = 286, H\(_2\)O = 18 ]

A68.4%

B62.9%

C9.7%

D6.3%

View Explanation & Discuss

Question 13

waec 2025

Biotechnology is applied in the following processes except

Abaking of bread

Bproduction of wine

Cproduction of antibiotics

Dmanufacturing of soap

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Question 14

waec 2025

If 25cm\(^3\) of a saturated solution contains 0.02 moles of the solute, determine the solubility of the solute.

A5.0 X 10\(^{-4}\) mol dm\(^{-3}\)

B0.8 mol dm\(^{-3}\)

C0.4 mol dm\(^{-3}\)

D5.0 X 10\(^{-2}\) mol dm\(^{-3}\)

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Question 15

waec 2025

The filter in a cigarette reduces the amount of nicotine inhaled by

Aadsorption

Babsorption

Cburning

Devaporation

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Question 16

waec 2025

In which of the following arrangements are the ions arranged in decreasing order of ionic size?

AF\(^-\),Na\(^+\), Mg\(^{2+}\), Al\(^{3+}\)

BNa\(^+\), Mg\(^{2+}\), Al\(^{3+}\),F\(^-\)

CAl\(^{3+}\), Na\(^+\), Mg\(^{2+}\), F\(^-\)

DAl\(^{3+}\), Mg\(^{2+}\), Na\(^+\), F\(^-\)

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Question 17

waec 2025

In the electrolysis of dilute hydrochloric acid at the anode

AOxygen gas is given off

Bhydrogen gas is given off

Cchlorine gas is given off

Dhydrogen chloride gas is given off

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Question 18

waec 2025

A covalent hydride which does not exist as a gas at room temperature is

AH\(_2\)O

BBH\(_3\)

CHCl

DH\(_2\)S

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Question 19

waec 2025

The number of moles of KOH present in 200cm\(^3\) of 5.6 g dm\(^{-3}\) solution is [KOH = 56 g mol\(^{-1}\)]

A2.01

B1.12

C0.02

D0.01

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Question 20

waec 2025

Which of the following compounds would readily undergo addition reaction?

Aethane

Bbutene

Cethanol

Dbenzene

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Question 21

waec 2025

How many pi-bond(s) is/are present in propene?

Athree

Bsix

Ctwo

Done

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Question 22

waec 2025

In a chemical reaction, ΔH is positive when

AΔH\(_{product}\) > ΔH\(_{reactants}\)

BΔH\(_{product}\) < ΔH\(_{reactants}\)

CΔH\(_{product}\) = ΔH\(_{reactants}\)

DΔH\(_{product}\) = 0

View Explanation & Discuss

Question 23

waec 2025

Alkali metals are good conductors of heat and electricity because they

Acontain delocalised electrons

Bare found in the d-block

Chave vibrating ions

Dare all metals

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Question 24

waec 2025

Ethanol could be prepared in the laboratory by

Areduction of ethanoic acid

Boxidation of primary alkanol

Coxidation of alkenes

Dhydration of ethene

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Question 25

waec 2025

Which of the following oxides would form two different types of acids when dissolved in water?

ACO\(_2\)

BNO\(_2\)

CSO\(_2\)

DSO\(_3\)

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Question 26

waec 2025

In the use of a universal indicator, red colour is an indication that the substance is a

Aconcentrated acid

Bconcentrated alkali

Cdilute acid

Ddilute base

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Question 27

waec 2025

The metal carbonate that would not decompose when heated strongly is

AAl\(_2\)CO\(_3\)

BCaCO\(_3\)

CMgCO\(_3\)

DNa\(_2\)CO\(_3\)

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Question 28

waec 2025

All the following compounds are ionic except

AAgCl

BKNO\(_3\)

CNO\(_2\)

D(NH\(_4\))\(_2\)CO\(_3\)

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Question 29

waec 2025

Which of the following bonds is not an intermolecular force?

AHydrogen bond

BVan der waal's

Cdipole-dipole

Dmetallic bond

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Question 30

waec 2025

Sodium chloride is used in the following processes except

Atreatment of water

Bmanufacturing of chloride

Cpreservation of food

Dseparation of soap glycerol

View Explanation & Discuss

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