**Core Concept**
Intra-arterial calcium gluconate infusion is a treatment for severe acid burns, specifically those caused by hydrofluoric acid (HF), which is a highly corrosive and toxic substance. Hydrofluoric acid burns occur when HF comes into contact with skin, leading to an ionic exchange between the acid and the skin, resulting in the release of fluoride ions.

**Why the Correct Answer is Right**
Hydrofluoric acid burns are unique in that they can cause severe systemic toxicity, including cardiac arrhythmias, hypocalcemia, and even death. The fluoride ions released from the acid bind to calcium ions, leading to a severe deficiency of calcium in the body. Intra-arterial calcium gluconate infusion is used to rapidly replenish calcium levels and prevent further fluoride ion-calcium ion binding, thereby reducing the risk of systemic toxicity. This treatment is most effective when administered early in the course of the burn.

**Why Each Wrong Option is Incorrect**
**Option A:** Nitric acid burns are not typically managed with intra-arterial calcium gluconate infusion. Instead, treatment focuses on debridement, wound care, and pain management.

**Option C:** Formic acid burns are not commonly associated with systemic toxicity or the need for intra-arterial calcium gluconate infusion. Treatment for formic acid burns typically involves wound care and supportive measures.

**Option D:** Hydrochloric acid burns are corrosive and can cause severe local tissue damage, but they are not typically managed with intra-arterial calcium gluconate infusion. Treatment focuses on debridement, wound care, and pain management.

**Clinical Pearl / High-Yield Fact**
Intra-arterial calcium gluconate infusion is a life-saving treatment for hydrofluoric acid burns, but it must be administered promptly to prevent systemic toxicity. Remember the mnemonic "HF" for hydrofluoric acid, which stands for "Highly Fatal" due to its potential for severe systemic toxicity.

**✓ Correct Answer: B. Hydrofluoric acid**