Question

Match list I with list II. Choose the correct matching codes from the choices given

	List I (Hydride)		List II (Type of hydride)
A.	$BeH_2$	1.	Complex
B.	$AsH_3$	2.	Lewis acid
C.	$B_2H_6$	3.	Interstitial
D.	$LaH_3$	4.	Covalent
E.	$LiAlH_4$	4.	Intermediate

• A. A-6, B-2, C-4, D-5, E-1
• B. A-6, B-2, C-4, D-3, E-1
• C. A-6, B-4, C-2, D-3, E-5
• D. A-5, B-4, C-2, D-3, E-1

Answer 1

Answer: (D)

$A-5$,
$B-4$,
$C-2$,
$D-3$,
$E-1$
Complex : Addition compounds which do not give all their constituent ions when dissolved in water. Here, the individual properties of ions are lost, e.g., $[Cu(NH_3)_4]SO_4$, $LiAlH_4$.
Lewis acid : Electron deficient species which gain electrons while forming a bond with Lewis bases.

$B_2H_6 + 2NH_3 \xrightarrow{\text{low temp}} B_2H_6 \cdot 2NH_3$ (adduct)
Interstitial metallic hydrides: Many $f$-block hydrides are non-stoichiometric, $e$.$g$., $LaH_n$ , $TiH_n$ , etc. where the chemical composition is variable $e$.$g$., $LaH_{2.87}$, $YbH_{2.5}$, etc. Such compounds are called interstitial compounds. $BeH_2$ : Intermediate hydride and polymeric in nature. $AsH_3$ : Covalent.