Which of the following elements does not form hydride by direct heating with dihydrogen?
In chemistry, a hydride is the anion of hydrogen, H−, or more commonly it is a compound in which one or more hydrogen centres have nucleophilic, reducing, or basic properties. In compounds that are regarded as hydrides, the hydrogen atom is bonded to a more electropositive element or groups.
All the elements except beryllium combine with hydrogen upon heating to form their hydrides, MH2.
2M + H2→ 2M+H- (M= Li, Na, K, Rb, Cs)
M’ + H2→ M’H2 (M’ = Mg, Ca, Sr, Ba, Ra)
Be cannot form hydride by this reaction because of the highest amount of ionization energy among alkali and alkali earth metals.
BeH2, however, can be prepared by the reaction of BeCl2 with LiAlH4
BeCl2 + LiAlH4→ 2BeH2 + LiCl + AlCl3
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