Hydrazine Formula – Structure, Properties, Uses, Sample Questions

Nitrogen is a fifteenth group nonmetallic element with symbol N and atomic number 7. It is the most abundant, colorless, odorless gas present in Earth’s atmosphere. Commercial Nitrogen is produced on large scale by fractional distillation of liquified air. Nitrogen is used to make fertilizers, dyes, explosives, food preservation, and many other industrial processes.

What is Hydrazine?

Hydrazine is an inorganic compound with the molecular formula N₂H₂. It is also called Diazane, Diamine, and Nitrogen Hydride. Hydrazine is safe until it’s in the form of Hydrazine hydrate (N₂H₄. x H₂O). It is a colorless and clear liquid that smells like ammonia and is highly reactive and should be handled with a lot of care.

Structure of Hydrazine

The chemical formula of hydrazine is  N₂H₄. Each nitrogen has 3 valence electrons of which 2 are elections are accepted hydrogen ions and the other electron is used in the formation of a single covalent bond between two individual Nitrogen atoms. The total number of bond pairs and lone pairs in hydrazine molecules are 5 and 2 respectively.

Hydrazine Structure

Production of Hydrazine

Pechiney-Ugine-Kuhlmann process: In this process, Ammonia reacts with Hydrogen peroxide and forms Hydrazine and water. The reaction involved is given below:

2NH₃ + H₂O₂ → N₂H₂ + 2H₂O

Raschig process: In this process, aqueous alkaline ammonia reacts with sodium hypochlorite to form Hydrazine, sodium hydroxide, and water. The reaction involved is as follows:

2NH₃ + NaOCl → N₂H₄ + NaCl + H₂O

Properties of Hydrazine

Physical properties of Hydrazine:

• The chemical formula of Hydrazine is N₂H₄.
• The molecular weight of Hydrazine is 32 g/mol.
• Density is equal to 1.02 g/cm³.
• Hydrazine smells like Ammonia.
• Hydrazine is colorless, oily, fuming liquid.
• The boiling point of Hydrazine is 114 ° C.
• The melting point of Hydrazine is 2 ° C.
• The refractive index is 1.46.

Chemical properties of Hydrazine

• Hydrazine on reaction with acids and a few metallic salts and produces those products which are utilized in the assembling of specific explosives and fungicides.
• Hydrazine on reacting with organic compounds and forms alkyl hydrazines.
• The combustion of Hydrazine in the presence of oxygen produces Nitrogen gas and water. This is an exothermic process and the reaction involved is as follows:

N₂H₄ + O₂ → N₂ + 2H₂O 

• Hydrazine reacts with chloramine to produce Nitrogen gas and Ammonium chloride. The reaction involved is as follows:

N₂H₄ + 2NH₂Cl → 2NH₄Cl + N₂

Uses of Hydrazine

• Hydrazine is used as a propellant in rockets and many other space vehicles.
• Hydrazine is used as a reducing agent.
• Hydrazine is used in the manufacturing of agricultural fungicides.
• Hydrazine is used as a corrosion-preventing agent in a cooling water reactor.
• Hydrazine is used as a precursor to blowing agents.
• Hydrazine is sometimes used on small scale to produce nitrogen gas.
• Hydrazine is used as a foaming agent in the production of polymer foams.

Harmful effects and safety measures for Hydrazine

Inhalation and exposure to hydrazine have a severe impact on human beings. It causes respiratory tract irritation, eye, and skin itching. We need to practice certain safety measures such as wearing an eye mask, and gloves while handling hydrazine. It is also advised to use a respirator if necessary. Wearing a safety suit and boots will ensure good safety.

Sample Questions 

Question 1: Mention any method of producing Hydrazine?

Answer:

The reaction between chloramine and ammonia results in the formation of Hydrazine and hydrochloric acid. The reaction involved is as follows:

NH₂Cl + NH₃ → H₂NNH₂ +HCl

Question 2: List the health hazards caused due to Hydrazine?

Answer:

Continuous exposure to Hydrazine may affect the central nervous system and respiratory system. Chronic exposure to Hydrazine may cause kidney and liver damage. Sometimes, it also causes irritation and itching to the skin and eyes.

Question 3: Explain how Hydrazine is used as rocket fuel?

Answer:

Hydrazine is allowed over catalyst like iridium metal, upheld by large surface area alumina, this makes it break down into ammonia, nitrogen gas, and hydrogen. The reaction involved is as follows:

N₂H₄  → N₂ + 2H₂

3N₂H₄  → 4NH₃ + N₂

These reactions are highly exothermic and produce enormous volumes of hot gas from a little volume of liquid, making hydrazine a genuinely proficient engine fuel or propellant.

Question 4: Explain the key features of the molecular structure of Hydrazine.

Answer:

• The distance between N and N single bond is 1.45 Å.
• It has  gauche conformation.
• The rotational barrier of Hydrazine is double that of ethane.
• Each H₂N−N subunit is pyramidal.

Question 5: List a few characteristic features of Hydrazine.

Answer:

Hydrazine is a highly unstable, poisonous substance that is colorless and smells like ammonia. It has a boiling point of 114 ° C and a melting point of 2 ° C.

Question 6: What reaction takes place when hydrazine is added to water?

Answer:

Hydrazine reacts with water to produce hydrazinium salts. The reactions involved are as follows:

N₂H₄ + H₂O ⇌ N₂H₅⁺ + OH^–

N2H5+ + H2O ⇌ N2H₆²⁺ + OH^–

Question 7:  What reactions take place when hydrazine reacts with excess oxygen.

Answer:

Hydrazine reacts with excess oxygen to produce nitrogen monoxide and nitrogen dioxide.The reactions involved is as follows:

N₂H₄ + 2O₂  → 2NO +2H₂O

N₂H₄ + 3O₂  → 2NO₂ + 2H₂O