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(a)(i) Define each of the following terms: I. normal salt. II. acid salt. (ii) ...

(a)(i) Define each of the following terms: I. normal salt. II. acid salt.
(ii) Tetraoxosulphate (VI) acid and sodium hydroxide react to produce salt and water. Write a balanced chemical equation fir the formation of: I. a normal salt; II. an acid salt.
(b)(i) Explain briefly the term acid-base indicator.
(ii) Copy and complete the following table.
Indicator , Colour in acidic medium , Colour in basic medium
Methyl orange
Phenolphthalein




(iii) For each of the following titrations, state the most suitable indicator: I. strong acid against strong base; II. strong acid against weak base; iii. weak acid against strong base.
(c) Baking soda and hydrochloric acid react according to the following equation:
NaHCO\(_{3(aq)}\) + HCI\(_{(aq)}\) ---> NaCl\(_{(aq)}\) CO\(_{2(g)}\) + H\(_2\)O\(_{(l)}\). Calculate the mass of baking soda that would produce 10g of ccrbon (IV) oxide. [H = 1.00, C = 12.0, 0 = 16.0, Na = 23.0]
(d) Give a reason why a given mass of sodium hydroxide pellets cannot be used to prepare a standard solution.
NaHCO\(_3\) + HCI --> NaCI + CO\(_2\) + H\(_2\)O
84g NaHCO\(_3\) --> 44g CO\(_2\)
Xg --> 10g CO\(_2\)
Xg = \(\frac{84 \times 10}{44}\)
= 19.09g
= 19.1g.
(d) give a reason why a given mass of sodium hydroxide pellets cannot be used to prepare a standard solution: Sodium hydroxide absorbs water/deliquescent and absorbs carbon IV oxide from air/and this would make mass taken unreliable/add to its mass.
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    Correct Answer: Option n
    Explanation:
    (a)(i) Define each of the following terms:
    I. Normal salt: Salt formed when all the replaceable hydrogen ions/replaceable hydrogen atoms of an acid are replaced by a metal/ammonium ion. Or a salt formed when all the OH\(^-\) of the alkali are replaced by an ionic group of an acid.
    II. Acid salt: Salt formed when only some part of the (replaceable) hydrogen ions/atoms of an acid are replace a metal.
    (ii) Tetraoxosulphate VI acid and sodium hydroxide react to produce s d water. Write a balanced chemical equation for the formation of:
    I. A normal salt: 2NaOH + H\(_2\)SO\(_4\) \(\to\) Na\(_2\)SO\(_4\) + 2H\(_2\)O.
    II. An acid salt: NaOH + H\(_2\)SO\(_4\) \(\to\) NaHSO\(_4\) + H\(_2\)O.

    (b)(i) Explain briefly the term acid-base indicator: It is either a weak acid or weak base which gives different colour in acid alkaline medium/depending on pH of the solution.
    (ii) Copy and complete the following table:
    (ii) Copy and complete the following table.
    Indicator , Colour in acidic medium , Colour in basic medium
    Methyl orange Red/Pink Yellow
    Phenolphthalein Colourless Pink/Red




    (iii) For each of the following titrations, state the most suitable indicator:-
    I. Strong acid against strong base – Methyl orange/methyl red/litmus/bromocresol blue or red.
    II. Strong acid against weak base – Methyl orange.
    III. Weak acid against strong base – Phenolphthalein.

    (c) Baking soda and hydrochloric acid react according to the following equation:
    NaHCO\(_{3(aq)}\) + HCl\(_{(aq)}\) \(\to\) NaCl\(_{aq}\) + CO\(_{2(aq)}\) + H\(_2\)O
    Calculate the mass of baking soda that would produce 10g of carbon(iv)oxide. [ H = 1, C = 12, O = 16, Na = 23 ]
    Relative molar mass (CO\(_2\)) = 12 + (2 x 16) = 44.
    Relative molar mass (NaHCO\(_3\)) = 23 + 1 + 12 + (3 x 16) = 84

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