Amyl nitrate is used as an antidote in which poisoning?
Arsenic poisoning
Hydrocyanide poisoning
Lead poisoning
Yellow poisoning
Ans. is 'b' i.e., Hydrocyanide poisoning * Amyl nitrite is used as an antidote in poisoning of hydrocyanic acid (cyanide).* Nitrates generate methaemoglobin which has high affinity for cyanide and forms cyanmethaemoglobin.* Cyanmethaemoglobin may again dissociate to release cyanide, therefore, sodium thiosulfate is given to form sod. thiocyanate which is poorly dissociable and is excreted in urine.
Toxicology