(a)(i) What is an acid?
(ii) List three chemical properties of tetraoxosulphate (VI) acid
(iii) Give two uses of tetraoxosulphate (VI) acid.
(b)(i) Describe a suitable laboratory procedure for preparing a sample of zinc tetraoxosulphate (VI) crystals, starting from zinc oxide.
(ii) Write two equations to show why zinc oxide is classified as an amphoteric oxide.
(c) Zinc reacts with copper (II) tetraoxosulphate (VI) according to the following equation: Zn + CuSO\(_4\) -> ZnSO\(_4\) + Cu
(i) State the type of reaction involved
(ii) Determine the mass of zinc that would react completely with 8.0g of copper (II) tetraoxosulphate (VI). [CuSO\(_4\) = 160; Zn = 65]
Explanation
(a)(i) An acid is a compound which produces hydroxonium ions in aqueous solutions
(ii)(1) Reacts with metal above hydrogen in dilute form to liberate hydrogen
(2) Reacts with bases to form salt and water only
(3) It liberates CO\(_2\) from trioxocarbonate (IV) Salts
(iii)(i) For making fertilizer (ii) For making drugs in pharmaceutical industries
(b)(i) Put dil. tetraoxosulphate (VI) acid in a beaker and add zinc oxide until more of the oxide dissolves. Filter off excess oxide. Pour filtrate in an evaporating dish and heat to concentrate it. Cool to obtain crystals. Filter off crystals and dry between filter paper.
(i) ZnO + 2HCI \(\to\) ZnCl\(_2\) + H2O
(ii) ZnO + 2NaON \(\to\) Na\(_2\)ZnO\(_2\) + H\(_2\)O
(c)(i) Displacement or Redox reaction
(ii) From the equation 160g of CuSO\(_4\) reacts with 65g of Zn 8g of CuSO\(_4\) would react with
\(\frac{65 \times 8}{160} = 3.25g\)