This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Forensic Medicine
Which acid does not show coagulation necrosis on contact? 
Select and explain. 
A. HC1, B. H,SO4, C. HF, D. HNO3
C: HF
Answer: C: HF 
Explanation: Ans: C. HF(Ref Reddy 34/e p493, 33/e p530; Principles of Clinical Toxicology 3/e p220; Forensic Pathology 3/ep241, 110).HF does not show coagulation necrosis on contact.Hydrofluoric acid causes liquefaction necrosis.