Question

The various types of hydrides and examples of each type are given below. {ll} Hydride type & Compound
(a) Electron deficient & (i) LiH
(b) Saline & (ii) CH$_4$
(c) Electron-precise & (iii) NH$_3$
(d) Interstitial & (iv) B$_2$H$_6$
(e) Electron rich & (v) CrH
Choose the correct matching from the codes given below

• A. (a)-(ii), (b)-(iv), (c)-(v), (d)-(iii), (e)-(i)
• B. (a)-(iv), (b)-(i), (c)-(ii), (d)-(v), (e)-(iii)
• C. (a)-(iv), (b)-(iii), (c)-(v), (d)-(ii), (e)-(i)
• D. (a)-(v), (b)-(iii), (c)-(iv), (d)-(ii), (e)-(i)
• E. (a)-(iv), (b)-(v), (c)-(i), (d)-(ii), (e)-(iii)

Hint:

Quick memory trick:
• Boron → Electron deficient
• Alkali metals → Saline
• Carbon compounds → Electron precise
• Transition metals → Interstitial
• Nitrogen → Electron rich (lone pair)

Answer 1

The Correct Option is B

Concept: Classification of Hydrides Hydrides are compounds of hydrogen with other elements and are classified based on their bonding nature and electron count:
• Electron-deficient hydrides: These have fewer electrons than required for normal covalent bonding. They form multi-center bonds. Example: Boron hydrides like $B_2H_6$
• Saline (ionic) hydrides: Formed by highly electropositive metals (alkali/alkaline earth metals). Contain $H^-$ ions. Example: $LiH$
• Electron-precise hydrides: These follow normal covalent bonding rules (octet rule satisfied). Example: $CH_4$
• Interstitial hydrides: Formed by transition metals. Hydrogen occupies interstitial spaces in metal lattice. Example: $CrH$
• Electron-rich hydrides: Contain lone pairs on the central atom (more electrons than required for bonding). Example: $NH_3$ Step-by-Step Matching: (a) Electron-deficient These hydrides lack sufficient electrons → typical of boron hydrides \[ \Rightarrow B_2H_6 \rightarrow (iv) \] (b) Saline hydride Formed by alkali metals → ionic nature \[ \Rightarrow LiH \rightarrow (i) \] (c) Electron-precise Follow octet rule exactly \[ \Rightarrow CH_4 \rightarrow (ii) \] (d) Interstitial hydride Formed by transition metals \[ \Rightarrow CrH \rightarrow (v) \] (e) Electron-rich hydride Contains lone pair on central atom \[ \Rightarrow NH_3 \rightarrow (iii) \] Final Matching: \[ (a)-(iv),\quad (b)-(i),\quad (c)-(ii),\quad (d)-(v),\quad (e)-(iii) \] \[ \boxed{\text{Correct Option: (B)}} \]