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Question
What do you understand by the term “non-stoichiometric hydrides”? Do you expect this type of the hydrides to be formed by alkali metals? Justify your answer.
Solution
Non-Stoichiometric hydrides are hydrogen-deficient compounds formed by the reaction of dihydrogen with d-block and f-block elements. These hydrides do not follow the law of constant composition. For example: LaH2.87, YbH2.55,
Alkali metals form stoichiometric hydrides. These hydrides are ionic in nature. Hydride ions have comparable sizes (208 pm) with alkali metal ions. Hence, strong binding forces exist between the constituting metal and hydride ion. As a result, stoichiometric hydrides are formed.
Alkali metals will not form non-stoichiometric hydrides.
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RELATED QUESTIONS
How do you expect the metallic hydrides to be useful for hydrogen storage? Explain.
Metal hydrides are ionic, covalent or molecular in nature. Among
Only one element of ______ forms hydride.
Which of the following statements are not true for hydrogen?
(i) It exists as diatomic molecule.
(ii) It has one electron in the outermost shell.
(iii) It can lose an electron to form a cation which can freely exist.
(iv) It forms a large number of ionic compounds by losing an electron.
Which of the following statements is correct?
(i) Hydrides of group 13 act as Lewis acids.
(ii) Hydrides of group 14 are electron deficient hydrides.
(iii) Hydrides of group 14 act as Lewis acids.
(iv) Hydrides of group 15 act as Lewis bases.
Which of the following statements is correct?
(i) Metallic hydrides are deficient of hydrogen.
(ii) Metallic hydrides conduct heat and electricity.
(iii) Ionic hydrides do not conduct electricity in solid-state.
(iv) Ionic hydrides are very good conductors of electricity in solid state.
What are metallic/interstitial hydrides? How do they differ from molecular hydrides?
