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AQA A2 Chemistry Acid-Base Equilibria 4 multiple-choice questions Watch

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    Hi everyone!
    I've just completed a multiple choice question paper and just want to double check the answers for four questions i found particularly difficult.
    Please could you help me out?

    The questions are:

    (1) Seperate 20cm^3 solutions of a weak acid and a strong acid of the same concentrations are titrated with NaOH solution. Which will be the same for these two titrations?
    a) Initial PH
    b) pH at equivalence point
    c) Volume of NaOH required to reach the equivalence point

    I put down c)

    (2) order in increasing pH (1.0 moldm^-3 aqeous solutions)
    a) Ammonium chloride
    b) Ammonium ethanoate
    c) Sodium ethanoate

    I put down CH3COONa, CH3NH4, NH4Cl

    (3) Which is a conjugate acid-base pair in following reaction?
    HNO3 + H2SO4 -> H2NO3 + HSO4

    a) HNO3 and H2SO4
    b) HNO3 and H2NO3
    c) HNO3 and HSO4
    d) H2NO3 and HSO4

    I put down HNO3 and H2NO3

    (4) An acid-base indicator, HIn, dissociates according to the following equation:

    In(aq) <-> H^+(aq) + In^-(aq)

    Which statement about this indicator is correct?

    a) In a strongly acidic solution colour B would be seen
    b) In a neutral solution the concentrations of HIn^-(aq) and In(aq) must be equal
    c) It is suitable for use in titrations involving weak acids and weak bases
    d) none of the above

    I put down none of the above
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    (Original post by MHMQ786)
    Hi everyone!
    I've just completed a multiple choice question paper and just want to double check the answers for four questions i found particularly difficult.
    Please could you help me out?

    The questions are:

    (1) Seperate 20cm^3 solutions of a weak acid and a strong acid of the same concentrations are titrated with NaOH solution. Which will be the same for these two titrations?
    a) Initial PH
    b) pH at equivalence point
    c) Volume of NaOH required to reach the equivalence point

    I put down c)

    (2) order in increasing pH (1.0 moldm^-3 aqeous solutions)
    a) Ammonium chloride
    b) Ammonium ethanoate
    c) Sodium ethanoate

    I put down CH3COONa, CH3NH4, NH4Cl

    (3) Which is a conjugate acid-base pair in following reaction?
    HNO3 + H2SO4 -> H2NO3 + HSO4

    a) HNO3 and H2SO4
    b) HNO3 and H2NO3
    c) HNO3 and HSO4
    d) H2NO3 and HSO4

    I put down HNO3 and H2NO3

    (4) An acid-base indicator, HIn, dissociates according to the following equation:

    In(aq) <-> H^+(aq) + In^-(aq)

    Which statement about this indicator is correct?

    a) In a strongly acidic solution colour B would be seen
    b) In a neutral solution the concentrations of HIn^-(aq) and In(aq) must be equal
    c) It is suitable for use in titrations involving weak acids and weak bases
    d) none of the above

    I put down none of the above
    1. :yep:
    2. :no:
    3. :yep:
    4. :yep: (assuming colour B is the RHS - which you haven't stated!)
 
 
 
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