Concept: Interstitial hydrides

Interstitial hydrides are formed when small hydrogen atoms occupy interstitial spaces in the crystal lattice of metals.

These are generally formed by:

• transition metals,
• especially those having comparatively larger atomic size and suitable lattice voids,
• metals that can absorb hydrogen into their metallic lattice.

Key trend

Among transition metals, many of the early transition metals form interstitial hydrides more readily than the later ones.

Examples include metals like: $\text{Sc, Ti, Zr, Hf, V, Nb, Ta, Cr}$

Check the given options

• A: Cr — Chromium is known to form interstitial hydride.
• B: Fe — Iron does not readily form a stable interstitial hydride under normal conditions in the standard JEE context.
• C: Mn — Manganese is not the usual expected answer for easy formation of interstitial hydride.
• D: Co — Cobalt also does not readily form such hydrides in the usual classification.

Conclusion

Therefore, the metal that forms interstitial hydride easily is: $\boxed{\text{Cr}}$

Comparison with stored answer

Stored correct answer = A

Derived answer = A

Hence, the derived answer agrees with the stored correct answer.