The alkali metals form salt-like hydrides by the direct synthesis at elevated temperature . The thermal stability of these hydrides decreases in which of the following orders ?

The alkali metals form salt-like hydrides by the direct synthesis at e

1.	The alkali metals form salt-like hydrides by the direct synthesis at elevated temperature . The thermal stability of these hydrides decreases in which of the following orders ?
Answer» `NAH gt LiH gt KH gt RbH gt CsH` `LiH gt NaH gt KH gt RbH gt CsH` `CsH gt RbH gt KH gt NaH gt LiH` `KH gt NaH gt LiH gt CsH gt RbH` Solution :As the size of alkalimetal ion increases , LATTICE ENTHALPY decreases and hence the stability of the corresponding metal hydride decreases . Thus , option (B) is CORRECT