JEE Main · 2019 · 08 Apr 2019 · Shift 2 · d and f Block Elements

Interstitial compounds form when small atoms such as H, C or N lodge in the gaps of a metal lattice. Trapping these atoms makes the solid very hard, raises its melting point, and leaves the metallic bonding, and hence the metallic conductivity, largely intact. What they are not is chemically reactive; the lattice is in fact stabilised and the compounds behave rather inertly. So the statement calling them chemically reactive is the incorrect one.