Chemistry JAMB, WAEC, NECO AND NABTEB Official Past Questions

22

Hypochlorous acid is used as a bleach because

  • A. it is a strong acid
  • B. it yields chlorine readily in pure water
  • C. it is an oxidising agent
  • D. it is a weak acid
  • E. it is a reducing agent
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23

The nucleus of an atom contains

  • A. protons only
  • B. neurons only
  • C. protons and electrons
  • D. neutrons and electrons
  • E. protons and neutrons
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24

An example of an alcohol is

  • A. CCl4
  • B. CH3COOH
  • C. CHCl3
  • D. C2H6
  • E. CH3OH
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25

When ammonia and hydrogen ion bond together to form ammonium ion, the bond formed is called

  • A. ionic bond
  • B. electrovalent bond
  • C. covalent bond
  • D. co-ordinate bond
  • E. hydrogen bond
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26

Which of the following is not a member of the homologous series of the paraffins (alkanes)?

  • A. C3H8
  • B. C5H12
  • C. C7H16
  • D. C15H32
  • E. C24H48
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27

Which of the following reactions does not take place in the smelting of iron in a blast furnace?

  • A. \(CaCO_{3(s)} → CaO_{(s)} + (CO_{2(g)}\)
  • B. \(C_{(s)} + O_{2(g)} → CO_{2(g)}\)
  • C. 3\(Fe{(s)} + 2O_{2(g)} → FeO_{4(s)}\)
  • D. \(SiO_{2(s)} + CaO_{(s)} → CaSiO_{3(s)}\)
  • E. \(CO_{2(g)} + C_{(s)} → 2CO_{(g)}\)
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28

Which of the following gases may not be dried with concentrated sulphuric acid?

  • A. HCl
  • B. N2
  • C. Cl2
  • D. SO2
  • E. NH3
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29

Brass and bronze are both metallic alloys. Which of the following constituents is common to both alloys?

  • A. Tin
  • B. Zinc
  • C. Copper
  • D. Lead
  • E. Aluminium
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30

If 30cm\(^3\) of oxygen diffuses through a porous pot in 7 seconds, how long will it take 60cm\(^3\) of chlorine to diffuse through the same pot, if the vapour densities of oxygen and chlorine are 16 and 36 respectively?

  • A. 9.3 sec
  • B. 14 sec
  • C. 21 sec
  • D. 28 sec
  • E. 30.3 sec
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31

The IUPAC names of the compounds CH3COOH and CH2=CH2 are respectively;

  • A. acetic acid and ethene
  • B. methanoic acid and ethene
  • C. methanoic acid and ethylene
  • D. ethanol and ethene
  • E. acetic acid and ethylene
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32

The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as;

  • A. saponification
  • B. dehydration
  • C. esterification
  • D. hydrolysis
  • E. hydration
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33

During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment,

  • A. the litmus turns blue but no gas is evolved
  • B. the litmus turns blue and oxygen is evolved
  • C. the litmus turns blue and hydrogen is evolved
  • D. the litmus turns red and oxygen is evolved
  • E. the litmus turns red and then becomes colourless
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34

A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by

  • A. boiling the water
  • B. adding excess calcium hydroxide
  • C. adding a calculated amount of calcium hydroxide
  • D. adding sodium carbonate
  • E. adding magnesium hydroxide
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35

Which of the following metals cannot replace hydrogen from water or steam?

  • A. Sodium
  • B. Magnesium
  • C. Iron
  • D. Calcium
  • E. Copper
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36

When each of the nitrates of Potassium, Magnesium and iron is heated,

  • A. all the nitrates decompose to their oxides
  • B. the nitrate of magnesium gives the nitrite and oxygen
  • C. the nitrates of magnesium and iron give the oxides
  • D. the nitrate of iron gives the nitrite and oxygen
  • E. the nitrate of the magnesium is not decomposed
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37

The pH of four solutions W, X, Y, Z are 4, 6, 8, 10 respectively, therefore

  • A. none of these solutions is acidic
  • B. the pH of Y is made more acidic by addition of distilled water
  • C. Z is the most acidic solution
  • D. W is the most acidic solution
  • E. X is neutral
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38

When large hydrocarbon molecules are heated at high temperature in the presence of a catalyst to give smaller molecules, the process is known as

  • A. disintegration
  • B. polymerization
  • C. cracking
  • D. degradation
  • E. distillation
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39

When heat is absorbed during a chemical reaction, the reaction is said to be

  • A. thermodynamic
  • B. exothermic
  • C. isothermal
  • D. endothermic
  • E. thermostatic
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40

When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are?

  • A. nitrogen and carbondioxide
  • B. the rare gases
  • C. nitrogen and oxygen
  • D. nitrogen and the rare gases
  • E. nitrogen, carbondioxide and the rare gases
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41

The oxidation state of chlorine in potassium chlorate is?

  • A. +1
  • B. +2
  • C. +3
  • D. +5
  • E. +7
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42

An element X forms the following compounds with chlorine; XCl4, XCl3, XCl2. This illustrates the

  • A. law of multiple proportions
  • B. law of chemical proportions
  • C. law of simple proportions
  • D. law of conservation of mass
  • E. law of definite proportions
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