Step 1: Identifying the nature of injury.
The injury described — a bone fracture — is specifically mentioned as “grievous hurt” under Section 320 of the IPC.
Step 2: Determining the offence.
When such grievous hurt is caused voluntarily (not accidentally), it is punishable under Section 325 of the IPC (or corresponding provision in the Bhartiya Nyaya Sanhita, 2023).
Step 3: Conclusion.
Since Rajesh intentionally struck Sunil, causing a fracture, he is guilty of voluntarily causing grievous hurt under Section 325.