question_answer

    (a) Predict the reaction, if any, between (i) zinc and silver nitrate solution, (ii) magnesium and iron (II) chloride solution, (iii) copper and magnesium sulphate solution. Write the equations, with state symbols, for the reaction.                       (b) A lump of element X can be cut by a   knife. During its reaction with water, X  floats and melts. What is X? Explain.  

Answer:

  Sol.         (a) (i) Zinc is more reactive than silver. It will    CD displace silver from silver nitrate solution.       (ii) Magnesium is more reactive than iron. It will displace iron from iron (II) chloride solution.  (iii) Copper is less reactive than magnesium. It will not displace magnesium form magnesium   sulphate solution. No reaction                                                      (3) (b) X is potassium (K). Potassium being soft can be cut by a knife and being lighter than water will float at the surface. The heat produced during reaction with water     will melt it.                                                          (2)