Chemistry Past Questions

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

109 questions
Question 1 of 20 109 total questions
Question 1
jamb 2025

The 5\(^{th}\) member of an alkyne series is 

AC\(_5\)H\(_8\)
BC\(_5\)H\(_{10}\)
CC\(_6\)H\(_{12}\)
DC\(_6\)H\(_{10}\)
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Question 2
jamb 2025

The reaction above illustrated is

Aspontaneous
Bendothermic
Cexothermic
Dreversible
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Question 3
jamb 2025

After breathing in a test tube that contains acidified K\(_2\)Cr\(_2\)O\(_7\), a man noticed a change in the colour of the acidified K\(_2\)Cr\(_2\)O\(_7\) from orange to green. This suggests the presence of 

Aalkanoic acid
Balkanal
Calkanol
Dalkanone
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Question 4
jamb 2025

Find the hydrogen ion, H\(^+\) concentration and hydroxide ion, OH\(^-\) concentration in 0.06 moldm\(^{-3}\) solution of H\(_2\)SO\(_4\).

A1.2 x 10\(^{-2}\) ; 8.3 x 10\(^{-13}\)
B1.2 x 10\(^{-1}\) ; 8.3 x 10\(^{-13}\)
C1.2 x 10\(^{-1}\) ; 8.3 x 10\(^{-14}\)
D1.2 x 10\(^{-2}\) ; 8.3 x 10\(^{-14}\)
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Question 5
jamb 2025

Bronze is used in making

Amusical instruments and ornaments
Bcoins and medals
Celectromagnets and cutlery
Daircrafts and ship
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Question 6
jamb 2025

In welding and cutting of metals, the organic gas commonly used in the heating process is

Amethane
Bpropene
Cbutane
Dethyne
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Question 7
jamb 2025

Freons pollution in the air are released from 

Afossil fuel
Baerosol can
Cphotosynthesis
Dorganic decay
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Question 8
jamb 2025

What is the product obtained at the anode in the electrolysis of concentrated sodium chloride using graphite electrode?

AChlorine gas
Boxygen gas
Cwater vapour
Dhydrogen gas
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Question 9
jamb 2025

How many molecules are there in 4.0 moles of glucose?

[Avogadro's number = 6.02 x  10\(^{23}\)]

A1.51 x 10\(^{23}\)
B2.41 x 10\(^{24}\)
C24.08 x 10\(^{24}\)
D1.51 x 10\(^{24}\)
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Question 10
jamb 2025

In the equation above, the expression for the equilibrium constant, k\(_c\) is

A\(\frac{[2XY_3]}{[X_2][3Y_2]}\)
B\(\frac{[X_2][3Y_2]}{2XY_3]}\)
C\(\frac{[XY_3]^2}{[X_2][Y_2]}\)
D\(\frac{[X_2][Y_2]^3}{[XY_3]^2}\)
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Question 11
jamb 2025

The fractions of crude oil are best separated by 

Asteam distillation
Bfractional crystallization
Cprecipitation
Dfractional distillation
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Question 12
jamb 2025

The above structure is 

Aalkylamine
Balkanone
Calkanamide
Damino acid
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Question 13
jamb 2025

The disintegration of radioactive phosphorus to silicon follows the first order kinetics with rate constant k\(_1\) = 3.85 x 10\(^{-3}\). Determine the half life of phosphorus.

A8 s
B180 s
C80 s
D100 s
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Question 14
jamb 2025

An importance of solubility is that it

Adetermines the amount of solute that can dissolve in a given amount of solvent
Blowers the vapour pressure of the liquid
Cenables us to know the chemical reactions of the gas with the liquid
Draises the boiling point of liquid
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Question 15
jamb 2025

A table in which metals are arranged in series according to their comparative tendencies to give up their valence electrons is 

Aperiodic table
Belectrochemical series
Ctable of elements
Dperiodicals
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Question 16
jamb 2025

Electron configuration of Chlorine atom is 

A1S\(^2\)2S\(^2\)2P\(^6\)3S\(^2\)3P\(^5\)
B1S\(^2\)2S\(^2\)2P\(^6\)3S\(^2\)3P\(^4\)
C1S\(^2\)2S\(^2\)2P\(^6\)3S\(^2\)3P\(^6\)
D1S\(^2\)2S\(^2\)2P\(^5\)3S\(^2\)3P\(^6\)
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Question 17
jamb 2025

The most suitable indicator to be used when reacting ethanedioic acid with potassium hydroxide is 

Aphenolphthalein
Bmethyl orange
Cmethyl red
Dmethyl purple
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Question 18
jamb 2025

The compound responsible for the pleasant scent of fruits and perfumes belongs to the class of 

Aalkanamide
Balkanone
Calkanal
Dalkanoate
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Question 19
jamb 2025

Na\(_2\)X ⇌  2Na\(^+\)  +  X\(^{2-}\)

The bond between Na and X is likely to be

Adative
Bionic
Cmetallic
Dcovalent
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Question 20
jamb 2025

The compound in which the oxidation state of nitrogen is + 3 is

AN\(_2\)O\(_5\)
BN\(_2\)O\(_3\)
CN\(_2\)O\(_4\)
DN\(_2\)O
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