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Chemistry Past Questions

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4,306 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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4,306 questions

Question 1 of 20 4,306 total questions

Question 1231

neco 2003

Which is NOT a synthetic polymer?

Anylon

BOrion

CPerspex

Dpolystyrene

Ewool

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Question 1232

neco 2003

The reaction C₂H₆ → C₂H + H₂ is known as

Adehydration

Bdehydrogenation

Cdisplacement

Dhydrogenation

Ereduction

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Question 1233

neco 2003

The boiling point of water is higher than the boiling point of ethanol because

Athe bonding in water is electrovalent (ionic) whereas the bonding in ethanol is convalent

Bthe hydrogen bonding between water molecules is stronger than the hydrogen bonding between ethanol molecules

Cwater has a higher lattice energy than ethanol.

Dwater has hydrogen bonding between its molecules but ethanol has no hydrogen bonging between its molecules;

Ewater is a better solvent than ethanol.

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Question 1234

neco 2003

B is an isotope of the element \(^{238} _{92}Ur\). The isotope B has

A46 protons and 119 neutrons

B92 protons and 92 neutrons

C92 protons and 146 neutrons

D92 protons and 238 neutrons

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Question 1235

neco 2003

The number of hydrogen ions in 1.0dm\(^3\) of a 0.25 mole tetraoxosulphate(Vl) acid solution is
[Avogadro c x 10\(^{23}\)]

A1.45x10²³

B1.50 x l0²³

C3.00x10²³

D3.15x10²³

E6.00x10²³

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Question 1236

neco 2003

Chlorine is used in water purification because it

Ableaches impurities in the water

Bdecolorizes water

Cdestroys bacteria

Dis extremely soluble in water

Eis pleasant tasting

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Question 1237

neco 2003

Which statement is NOT true about the composition of starch?

AIt contains only the atoms of carbon, hydrogen oxygen

BIt is a polysaccharide

CIts empirical formula is C₂H₂0.

DIt is made from the monomerC₆H₁₂O₆.

EThe hydrogen and oxygen atoms are in the ratio 2:1.

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Question 1238

waec 2003

Which of the following processes will pollute water?

AExposure of a body of water ultraviolet rays

BDischarge of industrial effluents effluents into water ways

CPassage of river water through a send bed

DAddition of a measured quantity of chlorine to water

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Question 1239

waec 2003

What are the two gases associated with the formation of acid rain?

ACO₂ and HCI

BCO₂ and N₂

CCO₂ and NO₂

DHCI ans SO₂

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Question 1240

waec 2003

When a sample of water was boiled, it lathered more readily with soap. it can be concluded that the sample most likely contained

Amagnesium tetraoxosulphate (VI)

Bsuspended solids

COrganic impurities

Dcalcium hydrogentrioxocarbonate (IV)

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Question 1241

waec 2003

What is the main impurity in haematite?

ACaSiO₃

BCaCO₃

CSiO₃

DFe₂O₃

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Question 1242

waec 2003

Which of the following compound is used for removing impurities from bauxite?

ANaOH

BCaCO₃

CNa₃AIF₆

DH₂SO₄

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Question 1243

waec 2003

What volume of 0.20 mol dm ^-3 NaOH solution would yield 5.0 g of NaOH on evaporation to dryness? [NaOH = 40g mol^-1]

A400 cm³

B625 cm³

C1000 cm³

D1600 cm ³

View Explanation & Discuss

Question 1244

waec 2003

When excess ethene is shaken with acidified KMnO₄ solution, the product obtained is

Aethane

Bethanal

Cethane - 1, 2 - diol

Dethanoic acid

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Question 1245

waec 2003

What process does the following equation represent ? n(C\(_{6}\)H\(_{10}\)O\(_{5}\)) + nH\(_{2}\)O → nC\(_{6}\)H\(_{12}\)O\(_{6}\) ?

APolymerization of glucose

BHydrolysis of starch

CFermentation of sugar

DDehydration of carbohydates

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Question 1246

waec 2003

The reaction of vegetable oil with a solution of wood ash is

Asaponification

Bneutralization

Chydrogenation

Desterification

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Question 1247

waec 2003

What is the organic product of the reaction of C2H 5OH with excess acidified K 2Cr 2O7(aq)?

ACH₃COOH

BC₂H₅OC₂H₅

CHCOOCH ₃

DC₂H₅CHO

View Explanation & Discuss

Question 1248

waec 2003

Which of the following substances could be responsible for the banana taste of a food flavour?

AMethylbenzene

BButanol

CEthanol

DPentylethanoate

View Explanation & Discuss

Question 1249

waec 2003

Wine containing 8% to 17% ethanol can be converted to gin containing about 40% ethanol by

Aevaporation

Bdistilation

Cfermentation

Doxidation

View Explanation & Discuss

Question 1250

waec 2003

A given fuel has an octane number of 100. This means that

Athe knocking tendency of the fuel is low

Bthe fuel is a mixture of several hydrocarbons

Ca large amount of alkanes is present in the fuel

Dthe fuel needs to be cracked before use

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