WAEC - Chemistry (2022)

  • 1
    The by-product of fermentation of sugar is
    Sagot
    (A)
    carbon(IV) oxide.
  • 2
    Which of the following sugars is a product of the condensation of monosaccharides?
    Sagot
    (B)
    maltose
  • 3
    The cleansing effect of soap is low in acidic water because of
    Sagot
    (A)
    the formation of unionized fatty acid.
  • 4
    The following compounds are condensation polymers except
    Sagot
    (D)
    polyethene
  • 5
    What amount of electricity is required to deposit one mole of aluminium from a solution of AlCl3?
    Sagot
    (C)
    Three Faradays
  • 6
    Which of the following compounds would react rapidly with bromine?
    Sagot
    (C)
    Hexene
  • 7
    Alkanols can be manufactured from alkenes by the initial reaction of alkenes with
    Sagot
    (B)
    concentrated tetraoxosulphate(VI) acid
  • 8
    Which of the following statements about the standard hydrogen electrode is not correct?
    Sagot
    (D)
    The temperature is kept at 20 °C
  • 9

    If 60 g of M combines with 24 g of oxygen, what would the empirical formula of the oxide be?

    ( molar mass of M = 120, O = 16)

    Sagot
    (C)
    MO\(_{3}\)
  • 10
    The products of the electrolysis of dilute sodium chloride using carbon electrodes are

    Anode Cathode
    Sagot
    (B)
    oxygen and hydrogen.
  • 11
    Determine the quantity of electricity used when a current of 0.20 amperes is passed through an electrolytic cell for 60 minutes.
    Sagot
    (D)
    720C
  • 12
    Oxochlorate(I) acid is used as a bleaching agent because it is
    Sagot
    (C)
    an oxidizing agent
  • 13
    The IUPAC name for CH\(_{3}\)CHCH\(_{3}\)CHCLCHCH\(_{3}\)CH\(_{2}\)CH\(_{3}\) is
    Sagot
    (D)
    3 - chloro - 2, 4 - dimethylhexane
  • 14
    A colourless gas with a pungent smell is evolved when dilute hydrochloric acid is added to a sample of a salt. The gas evolved could turn
    Sagot
    (B)
    acidified KMnO\(_{4}\) solution colourless
  • 15
    If 5.0 g of marble reacts with 25.0 cm3 hydrochloric acid, which of the following combinations has the fastest reaction rate?
    Sagot
    (C)
    Powdered marble and 2.5 mol dm\(^{-3}\) HCl\(_{(aq)}\)
  • 16
    Increasing the temperature generally
    Sagot
    (B)
    increases the solubility of a solid in a liquid but decreases the solubility of a gas in a liquid.
  • 17
    A white precipitate was formed when BaCl\(_{2(aq)}\) was added to an aqueous solution
    of a salt X. The precipitate dissolved in dilute HCl with rapid effervescence. Salt X is likely to contain
    Sagot
    (B)
    SO\(_{3}\) \(^{2-}\) ions
  • 18
    Before a reaction could take place, there should be
    Sagot
    (C)
    breakage of bonds of reactants
  • 19
    Consider the following reaction equation:
    CaO + SiO\(_{2}\) ------> CaSiO\(_{3}\)
    Silicon(IV) oxide is acting as
    Sagot
    (C)
    an acidic oxide
  • 20
    Which of the following acids would form normal salt only?
    Sagot
    (B)
    Trioxonitrate(V) acid
  • 21
    What is the partial pressure of oxygen at s.t.p. in a gaseous mixture containing 100 cm3 of oxygen and 900 cm3 of nitrogen gas?
    Sagot
    (B)
    0.1 atm
  • 22
    Graphite is used as a dry lubricant due to the presence of
    Sagot
    (D)
    layered structures
  • 23
    Which of the following gases is alkaline?
    Sagot
    (C)
    NH\(_{3}\)
  • 24
    Which of the following statements about an equilibrium system is correct?
    Sagot
    (A)
    Forward and backward reactions occur at the same rate
  • 25

    Consider the following reaction equation
    N\(_{2}\)(g) + 3H\(_{2(g)}\) ⇌ 2NH3(g) ∆H = -92kJ

    Increasing the temperature of the reaction would

    Sagot
    (D)
    decrease the yield of ammonia
  • 26
    When air in a syringe is compressed such that there is no change in temperature, the
    Sagot
    (B)
    pressure increases
  • 27

    Which of the following statements about liquids is/are true?


    I. Liquids maintain their volume at constant temperature.
    II. Liquids have fixed shape
    III. Liquids do not diffuse
    IV. Change in pressure affects volume of liquids

    Sagot
    (A)
    I only
  • 28
    A hydrogen chloride gas reacted with oxygen gas to yield water and chlorine gas. The mole ratio of the hydrogen chloride gas to water is
    Sagot
    (B)
    2:1
  • 29
    What number of moles of oxygen would exert a pressure of 10 atm at 320 K in an 8.2 dm\(^{3}\) cylinder?
    [R=0.082 atm dm\(^{-3}\) mol\(^{-1}\) K\(^{-1}\)]
    Sagot
    (C)
    3.13
  • 30
    If 50 cm\(^{3}\) of a saturated solution of KNO\(_{3}\) at 40 °C contained 5.05 g of the salt, its solubility at the same temperature would be
    [KNO\(_{3}\) = 101]
    Sagot
    (A)
    1.0 mol dm\(^{-3}\)
  • 31
    Which of the following elements would displace copper from a solution of copper ions?
    Sagot
    (C)
    lead
  • 32
    What is the percentage composition of carbon
    in Ca(HCO3)\(_{2}\) ?
    [ Ca = 40.0, 0= 16.0, C = 12.0, H= 1.0]
    Sagot
    (B)
    14.8%
  • 33
    Which of the following bond types is intermolecular?
    Sagot
    (B)
    Hydrogen bond
  • 34
    The maximum number of covalent bonds formed by nitrogen is
    Sagot
    (D)
    4
  • 35
    The IUPAC name of the compound CH3CH(CH3)CHCH2 is
    Sagot
    (C)
    3 - methyl but - 1 - ene
  • 36
    Ionization energy increases across the period in the periodic table because
    Sagot
    (B)
    effective nuclear charge increases
  • 37

    Which of the following properties indicate that an element is a metal. It


    I. reacts with oxygen to form an acidic oxide
    II. forms ionic chlorides
    III. has variable oxidation states
    IV. displaces hydrogen from dilute HCl

    Sagot
    (C)
    II and IV only
  • 38
    The electron configuration of carbon atom in its excited state is
    Sagot
    (C)
    1s\(^{2}\)2s\(^{1}\)2px\(^{1}\)2py\(^{1}\)2pz\(^{1}\)
  • 39

    An oxide has the following properties. It


    I. is a white powder
    II. reacts with HCI.
    III. reacts with NaOH
    IV. is insoluble in water
    The oxide is

    Sagot
    (B)
    amphoteric
  • 40
    Which of the following statements about atoms of a metal is correct? They
    Sagot
    (D)
    are held together by a sea of electron cloud
  • 41
    The atom with the electron configuration
    1s\(^{2}\)2s\(^{2}\)2p63s\(^{2}\)3p\(^{6}\)3d\(^{10}\)4s\(^{2}\)4p\(^{4}\) is in
    Sagot
    (A)
    period 4, p- block
  • 42
    Electropositivity of elements across the periodic table normally
    Sagot
    (C)
    decreases across the period
  • 43

    Consider the following table

    Substitute Meltig point / ºC Boiling  point / ºC
    P - 78 -25
    Q - 8 40
    R  - 6 150
    S 44 280


    Which of the substances is a liquid at room temperature and rapidly evaporates on exposure to air?

    Sagot
    (B)
    Q
  • 44
    Which of the following oxides is amphoteric?
    Sagot
    (C)
    Lead(II) oxide
  • 45
    Which of the following processes occur during fractional distillation of petroleum?
    Sagot
    (D)
    Evaporation and condensation