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Chemistry Past Questions

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1,623 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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1,623 questions

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Question 601

waec 1999

Geometric (cis-trans) isomerism is exhibited by

AC ₂H ₂CI ₂

BCH₂CI₅

CC ₄H ₁₀

DC₅H₁₂

View Explanation & Discuss

Question 602

waec 1999

Which of the following is a secondary alkanol?

AOHCI₂-CH₂OH

BH₂C=CH-CH₂OH

CCH ₃-CH(OH)-CH ₃

DCH₃-(CH₂)₃-CH₂OH

View Explanation & Discuss

Question 603

waec 1999

Alkanoates are produced from alkanols by

Afermentation

Bsaponification

Coxidation

Desterification

View Explanation & Discuss

Question 604

waec 1999

Which of the following compounds reacts with sodium hydroxide to form a salt?

ACH ₃CH ₂COOH

B(CH₃) ₃COH

CCH₃CH=CH ₂

DC ₆H ₁₂O ₆

View Explanation & Discuss

Question 605

waec 1999

Which of the following compounds is unsaturated?

A2-methylbutane

BChloromethane

CMethylbenzene

D1,2-dibromoethane

View Explanation & Discuss

Question 606

waec 1999

Which of the following is the most reactive towards bromine?

AMethane

BBenzene

CEthyne

DHexane

View Explanation & Discuss

Question 607

waec 1999

How many carbon atoms are present in one molecule of 2-methylpropane?

View Explanation & Discuss

Question 608

waec 1999

When dilute copper (ll) chloride solution is electrolysed, the reaction at the cathode is represented by the equation

ACu → Cu²⁺ + 2e-

BCu²⁺ + 2e- → Cu

C40H- - 4e- → O₂ + 2H₂O

D2CI- → CI₂ + 2e

View Explanation & Discuss

Question 609

waec 1999

Equal volumes of water were added to one mole of each of the following compounds. Which of them produced the largest number of ions

AGlucose

BSodium trioxonitrate (V)

CEthananoic acid

DSilver chloride

View Explanation & Discuss

Question 610

waec 1999

Which of the following is not correct about oxidation number convention? The oxidation number of a/an

Aelement in the free state is zero

Bmonatomic ion is equal to its charge

Calkali meta like sodium in its compounds is + 1

Datom of a diatomic molecules is + 2

View Explanation & Discuss

Question 611

waec 1999

What will be the effect of increase in pressure on the following system at equilibrium? 2NH_2(g) N_2(g) + 3H_2(g)

AActivation energy will decrease

Bthe forward reaction will be favoured

Cthe concentration of ammonia will increase

Dthe reaction will go to completion

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Question 612

waec 1999

Consider the reaction represented by the following equation: H_2(g) + 1_2(g) → 2HI_(g). The number of effective collisions of molecules of the reactants decreases as

Athe temperature is raised

Bthe pressure increased

Cthe volume of the system is increased

Da catalysty is intoduced into the system

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Question 613

waec 1999

Which of the following lowers the activation energy of a chemical reaction?

AFreezing mixture

BReducing agent

CWater

DCatalyst

View Explanation & Discuss

Question 614

waec 1999

The property of calcium chloride which makes it useful as a drying agent is that it is

Aionic

Bdeliquescent

Ca strong electrolyte

Da normal salt

View Explanation & Discuss

Question 615

waec 1999

If the solubility of KHCO₃ is 0.40 mole dm^{-3 at room temperature , calculate the mass of KHCO₃ in 100dm³ of the solution at this temperature. [KHCO₃ = 100hmol}

A4.0g

B10.0g

C40.0g

D100.0g

View Explanation & Discuss

Question 616

waec 1999

Which of the following compounds dissolves in water to form a solution with pH below 7?

ASodium tetraoxosulphate (VI)

BPotassium hydroxide

CAmmonium chloride

DSodium trioxocarbonate (IV)

View Explanation & Discuss

Question 617

waec 1999

Which of the following is an acid salt?

ANH₄CI

BMgSO₄ 7H₂O

CCH₃COONa

DNaHCO₃

View Explanation & Discuss

Question 618

waec 1999

An exothermic reaction is one which involves

Aattainment of dynamic equilibrium

Bloss of heat to the surrounding

Cevolution of gas as it proceeds

Dpositive change in value of enthalpy

View Explanation & Discuss

Question 619

waec 1999

30cm3 pf hydrogen at s.t.p combine with 20cm3 of oxygen to form steam according to the following equation 2H2(g) + O2(g) → 2H2O(g).

Calculate the total volume of the gaseous mixture at the end of the reaction

A50cm³

B35cm³

C30cm³

D25cm³

View Explanation & Discuss

Question 620

waec 1999

Helium is preferred to hydrogen in filling balloons because hydrogen

Ais inflammable

Bis diatomic

Cexhibits isotopy

Dis a component of water

View Explanation & Discuss

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