question_answer 53)

  Which of the following elements does not form hydride by direct heating with dihydrogen? (a)\[Be\]                                              (b)\[Mg\]                                            (c)\[Sr\]                                               (d) \[Ba\]

Answer:

  (a) \[Be{{H}_{2}}\]is not obtained by direct combination of beryllium and hydrogen. It is formed by reacting beryllium chloride with \[LiAl{{H}_{4}}\]. \[2BeC{{l}_{2}}+LiAl{{H}_{2}}\to 2Be{{H}_{2}}+AlC{{l}_{3}}+LiCl\]