What happens if you mix nitric acid with hydrazine?

When nitric acid is mixed with hydrazine, an extremely violent reaction occurs, with the main result being instantaneous self-ignition and a powerful explosion. Both of these substances are inherently highly reactive hazardous materials, and their mixture is even used as rocket propellant in military and aerospace fields, with tremendous power.
The core reaction after mixing: Explosion
The main reaction when nitric acid is mixed with hydrazine has two key characteristics:
Instantaneous self-ignition: When nitric acid (as a strong oxidizer) comes into contact with hydrazine (as a strong reducing agent), a violent oxidation-reduction reaction occurs immediately, and it will self-ignite without the need for any external ignition source. Chemically, this property is referred to as "self-ignition (Hypergolic)".
Product explosion: One of the direct products of this reaction is hydrazine nitrate (N₂H₅NO₃), which is an extremely unstable high-energy explosive. Under slight external energy disturbances (such as impact, friction, or static electric spark), it can undergo detonation.
A deadly name: "Devil's Venom"
The combination of nitric acid and hydrazine is so dangerous that it has been given the ominous title of "Devil's Venom". This terrifying name stems from a famous space disaster - the "Nedelin catastrophe".
Historical Tragedy: In 1960, a Soviet R-16 intercontinental missile, which used a combination of hydrazine and nitric acid as its propellant, was undergoing final preparations on the launch pad when an electronic fault accidentally activated the second-stage engine. This caused the entire rocket to explode on the launch pad, and a huge fireball engulfed the scene, resulting in the deaths of over a hundred technicians and scientists, including Marshal Nekhrilin, the commander of the Soviet Strategic Rocket Forces.
⚛️ How powerful is the explosion?
The nitramine generated by the reaction of hydrazine and nitric acid has an explosive power 1.42 times that of TNT. As a comparison, TNT is already a highly explosive substance. Here are the detonation parameters of nitramine, which can give you a more intuitive sense of its power:
Parameters Values Reference Explanation
Explosive velocity 8690 - 9300 m/s Much higher than TNT (about 6900 m/s), indicating that the explosion wave spreads extremely fast
Explosive heat Approximately 3869 kJ/kg The energy released per unit mass is extremely high, resulting in tremendous destructive power
Explosive gas volume 1001 L/kg Each kilogram of explosive can generate more than 1 cubic meter of high-temperature and high-pressure gas
Explosive temperature Approximately 3045 K About 2772 °C, sufficient to melt most metals
50% explosive temperature 307 °C When reaching this temperature, there is a 50% chance that the substance will undergo explosion
⚠️ Other dangers and key influencing factors
In addition to the direct explosion risk, there are some factors that will exacerbate the danger:
Extremely potent toxicity: Hydrazine is itself a highly toxic and carcinogenic substance. In experimental operations or inhalation of its volatile substances, it poses a serious threat to human health.
Instability and Side Effects: Under certain conditions (such as in the nuclear fuel reprocessing process), the solution system may also produce explosive intermediate products, such as the highly toxic and highly explosive azide (HN₃). Additionally, the presence of certain metal ions (such as technetium) can catalyze the reaction, increasing the risk of uncontrolled reactions.
Influencing factors: The intensity of the reaction is significantly affected by temperature, concentration, and mixing ratio. For instance, an increase in temperature will cause the reaction rate to accelerate sharply; a specific mixing ratio (i.e., the "optimal oxygen-fuel ratio") enables the reaction to be the most thorough and releases the maximum amount of energy.
Strictly prohibited!
The reaction between nitric acid and hydrazine has the characteristics of instantaneous self-ignition, the resulting product is a high-energy explosive, the process is highly prone to失控 and releases toxic substances, posing an unbearable and fatal risk to human safety. It is strictly prohibited for anyone to attempt this experiment under any conditions!