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    Hi, I really need help with these questions from the 2005 higher chemistry past paper - I don't understand how to do them at all! Thank you in advance!!

    1) Cl2(g) + H2O(l) <=> Cl-(aq) + ClO-(aq) + 2H+(aq)
    The addition of which of the following substances would move the above equilibrium to the right?
    A Hydrogen
    B Hydrogen Chloride
    C Sodium Chloride
    D Sodium Hydroxide


    2) Which of the following is a redox reaction?
    A Zn + 2HCl -> ZnCl2 + H2
    B NaOH + HCl -> NaCl + H2O
    C NiO + 2HCl -> NiCl2 + H20
    D CuCO3 + 2HCl -> CuCl2 +H2O + CO2

    I really do appreciate any help you can give me!
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    (Original post by lydofateapot)
    Hi, I really need help with these questions from the 2005 higher chemistry past paper - I don't understand how to do them at all! Thank you in advance!!

    1) Cl2(g) + H2O(l) <=> Cl-(aq) + ClO-(aq) + 2H+(aq)
    The addition of which of the following substances would move the above equilibrium to the right?
    A Hydrogen
    B Hydrogen Chloride
    C Sodium Chloride
    D Sodium Hydroxide


    2) Which of the following is a redox reaction?
    A Zn + 2HCl -> ZnCl2 + H2
    B NaOH + HCl -> NaCl + H2O
    C NiO + 2HCl -> NiCl2 + H20
    D CuCO3 + 2HCl -> CuCl2 +H2O + CO2

    I really do appreciate any help you can give me!
    Do you know how to find oxidation states of elements in compounds?
    And consider what is a product/reactant for the first question.
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    (Original post by lydofateapot)
    Hi, I really need help with these questions from the 2005 higher chemistry past paper - I don't understand how to do them at all! Thank you in advance!!

    1) Cl2(g) + H2O(l) <=> Cl-(aq) + ClO-(aq) + 2H+(aq)
    The addition of which of the following substances would move the above equilibrium to the right?
    A Hydrogen
    B Hydrogen Chloride
    C Sodium Chloride
    D Sodium Hydroxide
    Notice that there are hydrogen ions on the RHS of the equilibrium. Which of the four choices is good at reacting with hydrogen ions?


    2) Which of the following is a redox reaction?
    A Zn + 2HCl -> ZnCl2 + H2
    B NaOH + HCl -> NaCl + H2O
    C NiO + 2HCl -> NiCl2 + H20
    D CuCO3 + 2HCl -> CuCl2 +H2O + CO2

    I really do appreciate any help you can give me!
    Work out the oxidation states of the elements on each side, if they change then there is a redox reaction...
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    (Original post by charco)
    Notice that there are hydrogen ions on the RHS of the equilibrium. Which of the four choices is good at reacting with hydrogen ions?



    Work out the oxidation states of the elements on each side, if they change then there is a redox reaction...

    Thank you! I understand how to do the first question now! The answer is D right?
    How do you work out the oxidation states of the elements though?
    Thank you so much for your help though
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    (Original post by joostan)
    Do you know how to find oxidation states of elements in compounds?
    And consider what is a product/reactant for the first question.
    Thank you so much, I understand the first question now but no I don't know how to find the oxidation states?
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    (Original post by lydofateapot)
    Thank you so much, I understand the first question now but no I don't know how to find the oxidation states?
    Oxidation states follow very simple rules:

    1. The sum of the oxidation states equals the charge on the species.

    2. Uncombined elements have oxidation state zero.

    3. The more (most) electronegative element takes the negative oxidation state in a species.

    4. Hydrogen is always +1 (or -1)

    5. Oxygen is always -2 unless in peroxides, when it is -1

    6. The main group metals have oxidation states equal to their groups.

    With these rules you can work out the oxidation state of the majority of elements in the majority of systems.
 
 
 
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