2001 NECO Chemistry Past Questions & Answers

Question 1

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?

Accepted Answer

E. X2Y3

Answer

A. XY

Answer

B. X2Y

Answer

C. XY2

Answer

D. X3Y2

Question 2

Animal charcoal differs from wood charcoal in that it

Accepted Answer

E. is rich in phosphate content

Answer

A. has a dark colour

Answer

B. has a high carbon content

Answer

C. is a good absorbent

Answer

D. is crystalline.

Question 3

The atomic number of iron is 56. The number of unpaired electrons in the Fe3+ ion is

Accepted Answer

E. 5

Answer

A. 1

Answer

B. 2

Answer

C. 3

Answer

D. 4

Question 4

what dose the following equation illustrate? $ ^{238}U_{92} → ^{234}Th_{90} + ^4 He_2 $

Accepted Answer

E. spontaneous disintegration

Answer

A. Artificial radioactivity

Answer

B. nuclear fission

Answer

C. nuclear fusion

Answer

D. radio-decomposition

Question 5

The decreasing order of the oxidising power of the halogens is

Accepted Answer

C. F>Cl>Br>l

Answer

A. Br>I>Cl>F

Answer

B. F>I>Cl>Br

Answer

D. I>Br>Cl>F

Answer

E. Cl>Br>F>I

Question 6

in any chemical reaction, the total mass of products is always equal to that of the reactants. This Is statement of the law of:

Accepted Answer

A. conservation of matter.

Answer

B. Constant composition

Answer

C. definite proportions.

Answer

D. multiple proportions.

Answer

E. reciprocal proportions.

Question 7

The Atomic theory model which explains that electrons in an atom revolve round quantized energy levels is attributed to

Accepted Answer

B. Bohr.

Answer

A. Becquerel.

Answer

C. de Broglie.

Answer

D. Rutherford.

Answer

E. Thompson.

Question 8

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.

Accepted Answer

E. 50

Answer

A. 5

Answer

B. 12

Answer

C. 18

Answer

D. 45

Question 9

How much sodium hydroxide is required to make 250 cm3 of 0.1 molar solution? Na=23; 0=16; H=1]

Accepted Answer

D. 1 .0g

Answer

A. 10.0 g

Answer

B. 4.0g

Answer

C. 2.0 g

Answer

E. 0.1 g

Question 10

A measure of the degree of disorderliness in a chemical system is known as the

Accepted Answer

C. entropy

Answer

A. activation energy

Answer

B. enthalpy

Answer

D. equilibrium

Answer

E. free energy.

Question 11

Which method is NOT used to determine rate of a reaction?

Accepted Answer

B. change in equilibrium constant

Answer

A. change in amount of precipitate formed

Answer

C. change in intensity of colour

Answer

D. change in pH values.

Answer

E. change in total gas pressure

Question 12

Which compound is a product of the hydrolysis of the of CH$_3$COOC$_3$H$_7$ with aqueous sodium hydroxide?

Accepted Answer

A. CH3COONa

Answer

B. CH3COONaCCH3OH

Answer

C. CH3OH

Answer

D. C2H5OH

Answer

E. C3H7COONa

Question 13

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

Accepted Answer

A. butene.

Answer

B. butyne.

Answer

C. ethene.

Answer

D. propene.

Answer

E. propyne

Question 14

Which statement BEST describes the process of oxidation?

Accepted Answer

D. loss of electrons

Answer

A. addition of hydrogen

Answer

B. loss of oxygen

Answer

C. decrease in oxidation number

Answer

E. gain of elections.

Question 15

The maximum number of electrons that can occupy the shell having a principal quantum number of 3 is

Accepted Answer

D. 18

Answer

A. 3

Answer

B. 9

Answer

C. 10

Answer

E. 32

Question 16

The green colour solution of an Fe2 salt changes to a brown solution of an Fe3+ salt by

Accepted Answer

C. oxidation.

Answer

A. conversion.

Answer

B. elimination.

Answer

D. reduction.

Answer

E. substitution.

Question 17

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.?

Accepted Answer

B. 168 cm3

Answer

A. 164 cm3

Answer

C. 179.1.cm3

Answer

D. 201.5cm3

Answer

E. 546 cm3

Question 18

Detergents are better than soaps for washing in hard water because

Accepted Answer

D. they do not form insoluble calcium and magnesium salts.

Answer

A. hard water contains insoluble calcium salts.

Answer

B. they contain bleaching powder.

Answer

C. they contain palmitic acid.

Answer

E. they are organic compounds.

Question 19

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?

Accepted Answer

B. I and III

Answer

A. I and II

Answer

C. I and IV

Answer

D. II and III

Answer

E. II and IV

Question 20

Which element contains the greatest number of moles?

Accepted Answer

B. 48 g of Carbon

Answer

A. 8 g of Helium

Answer

C. 78 g of Potassium

Answer

D. 130g of Zinc

Answer

E. 216g of Sliver

Question 21

Faraday s first law of electrolysis can be expressed mathematically as

Accepted Answer

B. mαit

Answer

A. m=I/it

Answer

C. Q=it

Answer

D. QαI/it

Answer

E. Qαit

Question 22

Which of the following is TRUE of a catalyst? I. it alters the activation energy of a reaction II. it is effective in a reaction but cannot initiate a reaction III, it affects the equilibrium of a reversible reaction IV. it affects the overall reaction

Accepted Answer

A. I and II only

Answer

B. I, II and III only

Answer

C. II and III only

Answer

D. II, II and IV only

Answer

E. III and IV only

Question 23

Which metal will dissolve in aqueous sodium hydroxide?

Accepted Answer

A. aluminium

Answer

B. copper

Answer

C. iron

Answer

D. sikeer

Answer

E. tin

Question 24

NaCl(s) does NOT conduct electricity, but N(aq) does. This is because

Accepted Answer

C. NaCl(aq) contains mobile ions which Nacl,) does not contain.

Answer

A. NaCl(s) is non-ionic but NaCl(aq) is ion

Answer

B. NaCl(aq) contains mobile electrons, where absent in NaCl(s).

Answer

D. NaCl(s) ionizes partiality while NaCl(aq) iodizes completely.

Answer

E. NaCl(s) decomposes when heated but NCl(aq) is stable to heat. –

Question 25

The alloy used for welding and plumbing contains

Accepted Answer

E. lead and tin.

Answer

A. aluminum and copper.

Answer

B. copper and tin

Answer

C. iron and aluminum.

Answer

D. lead and antimony.

Question 26

The use of sulphur to vulcanize rubber is made to make it

Accepted Answer

D. tougher

Answer

A. blacker.

Answer

B. cheaper. .

Answer

C. more elastic

Answer

E. softer.

Question 27

Fructose and glucose are

Accepted Answer

D. isomers of each other

Answer

A. allotropes of each other.

Answer

B. both disaccharides

Answer

C. dimere of each other.

Answer

E. isotopes of each other

Question 28

Ethanol is a product of fermentation of simple sugars. Which method is used to separate ethanol from the other products?

Accepted Answer

D. fractional distillation

Answer

A. boiling off the ethanoic

Answer

B. filtration

Answer

C. fractional crystallisation

Answer

E. isomerisation

Question 29

Which compound will have the lowest boiling point?

Accepted Answer

E. (CH3)3CH

Answer

A. CH3OH

Answer

B. CH3COOH

Answer

C. CH3CHOH

Answer

D. C4H10

Question 30

The best way to distinguish between Na2CO3and NaHCO2 is by.

Accepted Answer

E. heating.

Answer

A. adding an acid.

Answer

B. adding an alkali.

Answer

C. dissolving in water.

Answer

D. exposing to air.

Question 31

The high boiling point of hydrogen fluoride can be explained in terms of

Accepted Answer

E. hydrogen bonds.

Answer

A. covalent bonds.

Answer

B. dative bonds.

Answer

C. dipole-dipole bonds.

Answer

D. electrovalent (ionic) bonds

Question 32

Which compound can be used as a reducing agent in a reaction?

Accepted Answer

E. Na2SO3

Answer

A. Cl2

Answer

B. KMnO4

Answer

C. KCr2O7

Answer

D. MnO2

Question 33

To test for the presence of chloride ions in ion, correct sequence of reagents to use is

Accepted Answer

E. HNO3(aq) then AgNO3(aq).

Answer

A. Ba(NO3)2(aq) then HNO3(aq).

Answer

B. HCl(aq) then Ba(NO3)2(aq).

Answer

C. HCl(aq) then Ag3(aq).

Answer

D. HNO3(aq) then fresh FeSO4(aq).

Question 34

What is the ratio of the rate of diffusion of carbon(IV) oxide to that of propane, under the same conditions? [H = 1; C= 12; 0= 161

Accepted Answer

C. 2:01

Answer

A. 1:01

Answer

B. 1:01

Answer

D. 2:03

Answer

E. 3:01

Question 35

The oxidation number of X in $XO_{4}^{3-}$ is

Accepted Answer

E. 5

Answer

A. 1

Answer

B. -2

Answer

C. 3

Answer

D. 4

Question 36

Which compound is a component of baking powder?

Accepted Answer

D. NaHCO3

Answer

A. Na2CO3

Answer

B. Na2SO4

Answer

C. KH2CO3

Answer

E. NaHSO4

Question 37

White is NOT a property of metals?

Accepted Answer

D. have many oxidation states

Answer

A. ductile:

Answer

B. malleable

Answer

C. conduct heat and electricity

Answer

E. high melting points anti boiling points

Question 38

The Kinetic theory can NOT be used to explain

Accepted Answer

A. allotropy.

Answer

B. Brownian movement.

Answer

C. diffusion.

Answer

D. Tyndal effect.

Answer

E. vaporization.

Question 39

On exposure to hydrogen sulphide, moist lead (II) ethanoate paper turns

Accepted Answer

A. black

Answer

B. blue

Answer

C. green

Answer

D. white

Answer

E. yellow

Question 40

20 cm3 of 0.09 mol dm3 solution of tetraoxosuiphate (Vi) acid requires 30cm3 of sodium hydroxide solution for complete neutralization. The molar concentration of sodium hydroxide is [H = 1; S = 32; 0 = 16; Na = 23]

Accepted Answer

B. 0.12 mol dm3

Answer

A. 0.03 mol dm3

Answer

C. 0.27 mol dm3

Answer

D. 0.45 mol dm3

Answer

E. 0.90 mol dm3

Question 41

The position of an element in the Periodic Table is determined by?

Accepted Answer

D. the number of protons in its atom.

Answer

A. its atomic radius.

Answer

B. its density.

Answer

C. its relative atomic mass.

Answer

E. the number of neutrons in its atoms

2001 NECO Chemistry Past Questions

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