WAEC - Chemistry (2022)

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

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

    Anode Cathode
    Trả lời
    (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.
    Trả lời
    (D)
    720C
  • 12
    Oxochlorate(I) acid is used as a bleaching agent because it is
    Trả lời
    (C)
    an oxidizing agent
  • 13
    The IUPAC name for CH\(_{3}\)CHCH\(_{3}\)CHCLCHCH\(_{3}\)CH\(_{2}\)CH\(_{3}\) is
    Trả lời
    (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
    Trả lời
    (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?
    Trả lời
    (C)
    Powdered marble and 2.5 mol dm\(^{-3}\) HCl\(_{(aq)}\)
  • 16
    Increasing the temperature generally
    Trả lời
    (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
    Trả lời
    (B)
    SO\(_{3}\) \(^{2-}\) ions
  • 18
    Before a reaction could take place, there should be
    Trả lời
    (C)
    breakage of bonds of reactants
  • 19
    Consider the following reaction equation:
    CaO + SiO\(_{2}\) ------> CaSiO\(_{3}\)
    Silicon(IV) oxide is acting as
    Trả lời
    (C)
    an acidic oxide
  • 20
    Which of the following acids would form normal salt only?
    Trả lời
    (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?
    Trả lời
    (B)
    0.1 atm
  • 22
    Graphite is used as a dry lubricant due to the presence of
    Trả lời
    (D)
    layered structures
  • 23
    Which of the following gases is alkaline?
    Trả lời
    (C)
    NH\(_{3}\)
  • 24
    Which of the following statements about an equilibrium system is correct?
    Trả lời
    (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

    Trả lời
    (D)
    decrease the yield of ammonia
  • 26
    When air in a syringe is compressed such that there is no change in temperature, the
    Trả lời
    (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

    Trả lời
    (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
    Trả lời
    (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\(^{-1}\)]
    Trả lời
    (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]
    Trả lời
    (A)
    1.0 mol dm\(^{-3}\)
  • 31
    Which of the following elements would displace copper from a solution of copper ions?
    Trả lời
    (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]
    Trả lời
    (B)
    14.8%
  • 33
    Which of the following bond types is intermolecular?
    Trả lời
    (B)
    Hydrogen bond
  • 34
    The maximum number of covalent bonds formed by nitrogen is
    Trả lời
    (D)
    4
  • 35
    The IUPAC name of the compound CH3CH(CH3)CHCH2 is
    Trả lời
    (C)
    3 - methyl but - 1 - ene
  • 36
    Ionization energy increases across the period in the periodic table because
    Trả lời
    (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

    Trả lời
    (C)
    II and IV only
  • 38
    The electron configuration of carbon atom in its excited state is
    Trả lời
    (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

    Trả lời
    (B)
    amphoteric
  • 40
    Which of the following statements about atoms of a metal is correct? They
    Trả lời
    (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
    Trả lời
    (A)
    period 4, p- block
  • 42
    Electropositivity of elements across the periodic table normally
    Trả lời
    (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?

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