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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 121

waec 2021

Which of the graphs illustrates the variation of the pH of a given volume of strong acid solution (y-axis) with the volume of strong base titrated against its (x-axis)?

BII

CIII

DIV

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Question 122

waec 2021

Which of the following illustrates the variation of the rate of evolution of gas from a given length of magnesium ribbon (y-axis) with an increase in the concentration of the added (x-axis)?

BII

CIII

DIV

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Question 123

waec 2021

Which of the following pairs of compounds would form a precipitate when their aqueous solutions are mixed?

ANaCl and KNO\(_{3}\)

BKCL and NaNO\(_{3}\)

CK\(_{2}\)SO\(_{4}\) and BaCl\(_{2}\)

DNH\(_{4}\)NO\(_{3}\) and CO\(_{3}\)

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Question 124

waec 2021

The alkanol represented by the structure above is

Aprimary and dihydric

Bsecondary and monohydric

Ctertiary and dihydric

Dsecondary and dihydric

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Question 125

waec 2021

If humid air is polluted by chlorine discharged, the air can be restored by sprinkling

Asolid MnO\(_{2}\)

Bacidified KMnO\(_{4}\)

Cacidified FeSO\(_{4}\)

Dsaturated NaCl(aq)

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Question 126

waec 2021

Cathodic protection of metals is based on

Astandard electrode potential of hydrogen

Bits electrical conductivity

Cnature of oxides formed

Drelative tendencies of oxidation

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Question 127

waec 2021

What is the relative molecular mass of the compound below?

What is the relative molecular mass of the compound below [H = 1.0; C = 12.0; O = 16.0] - SchoolNGR

[H = 1.0; C = 12.0; O = 16.0]

A137

B136

C64

D59

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Question 128

waec 2021

The ratio of carbon atoms of hydrogen atoms in a hydrocarbon is 1:2. If its molecular mass is 56, what is its molecular formula?

AC\(_{3}\)H\(_{6}\)

BC\(_{4}\)H\(_{8}\)

CC\(_{2}\)H\(_{4}\)

DCH\(_{2}\)

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Question 129

waec 2021

Which of the following oxide causes acid rain?

ACO

BNO

CH\(_{2}\)O\(_{2}\)

DNO\(_{2}\)

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Question 130

waec 2021

The hydrolysis of proteins by diluting mineral acids produces

Asucrose

Bglucose

Camino acids

Dfatty acids

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Question 131

waec 2020

An example of a biodegradable pollutant is?

Aplastic

Bsewage

Ccarbon (II) oxide

Dhydrogen sulphide

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Question 132

waec 2020

Calcium chloride is an ionic compound. Which of the following statements account for its ionic character?

I. Calcium has high ionization energy. II. Calcium has low ionization energy. III. Chlorine has high electron affinity. IV. Chlorine has high Ionization energy.

AI and Il only

BI, II and IV only

CII, IIl and IV only

DI, II, III and IV

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Question 133

waec 2020

Dilution factor is the?

Aamount of distilled water that is added to the concentrated solution to dilute it

BQuantity of distilled water added to l dm\(^3\) of the concentrated solution to give the dilute solution

Cnumber of times the volume of the concentrated solution is diluted to give the dilute solution

Dact of diluting the concentrated solution to obtain the dilute solution

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Question 134

waec 2020

which of the following quantities is a molar quantity?

AMolarity

BMolar mass

CMass concentration

DMolality

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Question 135

waec 2020

Which of the following processes is not exhibited by atoms in order to attain more stable electron configuration?

AGaining of electrons

BHybridization of orbitals

CLosing electrons

DSharing electron

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Question 136

waec 2020

The atomic number of an atom would be equal to its mass number if it

Ahas a totally filled valence shell

Bhas a high charge to mass ratio

Cdoes not contain neutrons

Dexhibits isotopy

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Question 137

waec 2020

How many electrons does \({31}_{15}\)P\(^3-\) contain?

A12

B15

C16

D18

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Question 138

waec 2020

Consider the reaction represented by the following equation:

AgNO\(_3\) + NaCl → AgCl + NaNO\(_3\).

The steps that could be taken to obtain pure dry sample of AgCI (s) from the mixture includes

Aheating to saturation and drying

Bfiltering and evaporation to dryness

Cfiltering, washing and drying

Dcrystallizing and allowing to cool

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Question 139

waec 2020

The metallic bond in magnesium is stronger than that in calcium because magnesium has a

Alarger atomic size.

Bsmaller atomic size

Cgreater number of valence electrons

Dlower melting point

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Question 140

waec 2020

Which of the following arrangement of elements is in decreasing order of electronegativity?

ANa, Mg, Al, Si, P

BNa, A1, Mg, P, Si

CP, Mg, Na, Si, Al

DP, Si, Al, Mg, Na

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