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Chemistry Past Questions

Study and practice Chemistry past questions with answers and detailed explanations. Then test your knowledge using our interactive CBT practice platform and prepare confidently for your upcoming examinations.

41 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10
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Past Questions

41 questions
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Question 1 of 20 41 total questions
Question 1
neco 2001
Which compound is a component of baking powder?
ANa2CO3
BNa2SO4
CKH2CO3
DNaHCO3
ENaHSO4
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Question 2
neco 2001

if an element X with atomic number 13 combines with an element Y whose atomic number is 8 the most likely formula of the compound formed between X and Y is?

AXY
BX2Y
CXY2
DX3Y2
EX2Y3
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Question 3
neco 2001
When an electric current is passed through a solution containing dilute tetraoxosulphate (Vi) acid, 190 cm3 of hydrogen gas is evolved. if the measurements were made at 26°C and 736 mmHg, what is the volume of hydrogen at s.t.p.?
A164 cm3
B168 cm3
C179.1.cm3
D201.5cm3
E546 cm3
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Question 4
neco 2001
A measure of the degree of disorderliness in a chemical system is known as the
Aactivation energy
Benthalpy
Centropy
Dequilibrium
Efree energy.
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Question 5
neco 2001
Fructose and glucose are
Aallotropes of each other.
Bboth disaccharides
Cdimere of each other.
Disomers of each other
Eisotopes of each other
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Question 6
neco 2001
Detergents are better than soaps for washing in hard water because
Ahard water contains insoluble calcium salts.
Bthey contain bleaching powder.
Cthey contain palmitic acid.
Dthey do not form insoluble calcium and magnesium salts.
Ethey are organic compounds.
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Question 7
neco 2001
Which method is NOT used to determine rate of a reaction?
Achange in amount of precipitate formed
Bchange in equilibrium constant
Cchange in intensity of colour
Dchange in pH values.
Echange in total gas pressure
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Question 8
neco 2001
Ethanol is a product of fermentation of simple sugars. Which method is used to separate ethanol from the other products?
Aboiling off the ethanoic
Bfiltration
Cfractional crystallisation
Dfractional distillation
Eisomerisation
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Question 9
neco 2001
To test for the presence of chloride ions in ion, correct sequence of reagents to use is
ABa(NO3)2(aq) then HNO3(aq).
BHCl(aq) then Ba(NO3)2(aq).
CHCl(aq) then Ag3(aq).
DHNO3(aq) then fresh FeSO4(aq).
EHNO3(aq) then AgNO3(aq).
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Question 10
neco 2001
NaCl(s) does NOT conduct electricity, but N(aq) does. This is because
ANaCl(s) is non-ionic but NaCl(aq) is ion
BNaCl(aq) contains mobile electrons, where absent in NaCl(s).
CNaCl(aq) contains mobile ions which Nacl,) does not contain.
DNaCl(s) ionizes partiality while NaCl(aq) iodizes completely.
ENaCl(s) decomposes when heated but NCl(aq) is stable to heat. –
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Question 11
neco 2001
The green colour solution of an Fe2 salt changes to a brown solution of an Fe3+ salt by
Aconversion.
Belimination.
Coxidation.
Dreduction.
Esubstitution.
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Question 12
neco 2001
A gas X diffuse through porous partition at the rate of 3 cm3 per second. Under the same condition hydrogen diffused at the rate of 15 cm3 per second.

What is the 42. relative molecular mass of X.
A5
B12
C18
D45
E50
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Question 13
neco 2001
Faraday s first law of electrolysis can be expressed mathematically as
Am=I/it
Bmαit
CQ=it
DQαI/it
EQαit
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Question 14
neco 2001
An experiment to test the conductance of 0,1 M solutions of the substances listed below was perform.
I ammonia
II ammonium chloride
III ethanoic acid
IV sodium ethanoate
Which pair of substances show the least conductance?
AI and II
BI and III
CI and IV
DII and III
EII and IV
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Question 15
neco 2001
The best way to distinguish between Na2CO3and NaHCO2 is by.
Aadding an acid.
Badding an alkali.
Cdissolving in water.
Dexposing to air.
Eheating.
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Question 16
neco 2001
The Kinetic theory can NOT be used to explain
Aallotropy.
BBrownian movement.
Cdiffusion.
DTyndal effect.
Evaporization.
View Explanation & Discuss
Question 17
neco 2001

The molar mass of a compound X is 56. its empirical formula is CH2. X is

Abutene.
Bbutyne.
Cethene.
Dpropene.
Epropyne
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Question 18
neco 2001
Which compound will have the lowest boiling point?
ACH3OH
BCH3COOH
CCH3CHOH
DC4H10
E(CH3)3CH
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Question 19
neco 2001
The Atomic theory model which explains that electrons in an atom revolve round quantized energy levels is attributed to
ABecquerel.
BBohr.
Cde Broglie.
DRutherford.
EThompson.
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Question 20
neco 2001
White is NOT a property of metals?
Aductile:
Bmalleable
Cconduct heat and electricity
Dhave many oxidation states
Ehigh melting points anti boiling points
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