Ammonia(NH3)-Structure, Physical & Chemical Properties, Preparation, Uses, FAQs

Let’s learn about ammonia in detail, including its structure, properties and uses.

Ammonia

Ammonia is nitrogen and hydrogen-based chemical. It is made up of one nitrogen and three hydrogen atoms. NH3 is its chemical formula.

Formation of ammonia by the decomposition of nitrogenous organic matter urea (NH2CONH2).

The natural breakdown of animal and plant bodies produces ammonia because the nitrogen compounds present in them decompose as they die or decay, resulting in ammonia. Ammonia can also be found in the soil as an ammonium salt.

Ammonia Structure- NH3

The ammonia molecule is produced when three sp3 hybrid orbitals of nitrogen and three s orbitals of hydrogens collide. A lone pair of electrons occupy the 4th sp3 hybrid orbital of nitrogen. The ammonia molecule has a trigonal pyramidal structure as a result of this.

The H-N-H angle is 107.8 , while the N-H bond length is 101.7 pm. Due to lone pair-bond pair repulsion, which tends to push the N-H bond slightly inwards, the H-N-H bond angle is somewhat less than the tetrahedral angle of 10928′. Ammonia is linked in liquid and solid forms due to hydrogen bonding.

Ammonia (NH₃) is a colorless gas with a sharp, pungent odor. It is a compound of nitrogen and hydrogen and plays a crucial role in both the industrial sector and biological processes.
Ammonia (NH₃) is a colorless gas with a sharp, pungent odor. It is a compound of nitrogen and hydrogen and plays a crucial role in both the industrial sector and biological processes.

Formation of Ammonia molecule

Physical Properties of Ammonia

PropertyDescription
Physical StateColourless gas
OdourDistinct pungent odour, known as ammoniacal odour
Density Relative to AirLighter than air, gathered via air displacement downward
Effect on InhalationCauses tears to well up in the eyes when inhaled quickly
Liquefaction ConditionsEasily liquefies at room temperature under a pressure of 8 to 10 atmospheres
Boiling Point under 1 atm–33.5°C (239.6K)
Enthalpy of VaporizationHigh (1370J/g), used in ice-making equipment and refrigeration systems
Freezing PointFreezes into a white crystalline solid at –77.8°C (195.3K)
Water SolubilityExtremely high; one volume of water dissolves about 1300 volumes of ammonia gas
Collection MethodCannot be collected in water due to its high water solubility

Chemical Properties of Ammonia

  • Ammonia is very soluble in water due to its basic composition. Due to the production of OH ions, its aqueous solution is weakly basic.

NH3(g)+H2O(I) ⇋ NH4OH(aq) ⇋ NH4+(aq)+OH(aq)

Because it is basic, it turns moist red litmus blue and neutralises acids in both dry and wet states, generating their corresponding salts.

NH3+HCl → NH4Cl

2NH4OH+H2SO4 → (NH4)2SO4+2H2O

  • Ammonia functions as a Lewis base due to the existence of a lone pair of electrons on the nitrogen atom. Consequently, it can easily donate its electron pair to establish a coordinate bond with electron-deficient compounds such as BF3 or transition metal cations possessing unoccupied d-orbitals to form complexes. As an example,

Ag+(aq)+2NH3(aq) → [Ag(NH3)2]+(aq)

Cu2+(aq)+4NH3(aq) → [Cu(NH3)4]2+(aq)

Thus, ammonia acts as a ligand.

  • Ammonia is neither a fuel nor a fuel supporter when it comes to combustion. In the presence of oxygen, however, it produces dinitrogen and water.

4NH3+3O2→2 N2+6H2O

  • Ammonia is oxidised to dinitrogen gas when it passes through a solution of calcium hypochlorite (bleaching powder), bromine water, or heated copper oxide.

4NH3+3Ca(OCl)2 → 2 N2+3CaCl2+6H2O

8NH3+3Br2 → N2+6NH4Br

2NH3+3CuO+Heat → 3Cu+N2+3H2O

Ammonia is oxidised to nitric oxide when it is passed through Pt/Rh gauze at 500 K under a pressure of 9 bar with an excess of air. Ostwald’s technique uses this reaction as the starting point for making nitric acid.

Preparation of Ammonia

  • Using a strong base to heat ammonium salts: Ammonia is made on a small scale by heating ammonium salts with a strong base.

(NH4)2SO4 + 2NaOH + Heat→2NH3 + 2H2O + Na2SO

NH4Cl+KOH+Heat→NH3+H2O+KCl

  • Ammonia is made in the lab by heating a mixture of slaked lime and ammonium chloride.

2NH4Cl+Ca(OH)2+Heat→2NH3+2H2O+CaCl2

  • The hydrolysis of metal nitrides, such as magnesium and aluminium nitride, with water or alkalis, can also yield ammonia gas.

Mg3 N2+6H2O→2NH3+3Mg(OH)2

AlN+3H2O→NH3+Al(OH)3

By passing ammonia gas over quicklime, it is dried (CaO). Because ammonia is a basic gas, it cannot be dried by passing it through concentrated sulphuric acid or phosphorus pentoxide, as it will react with them to generate ammonium sulphate or ammonium phosphate. Calcium chloride cannot be used to dry ammonia gas because calcium chloride creates ammoniates.

Preparation of Ammonia by Haber Process

On a commercial scale, ammonia is manufactured by Haber’s process.

N2(g) + 3H2(g) ⇌ 2NH3(g) ; ΔH=–92.4kJ/mol

This is a reversible, exothermic reaction that occurs when the volume decreases. As a result, according to Le Chatelier’s principle, the best conditions for producing ammonia are:

  1. Low temperature: Because the forward process is exothermic, the generation of ammonia is favoured at low temperatures. The rate of reaction, however, will be slow at low temperatures. The reaction’s optimal temperature has been determined to be around 700K.
  2. High pressure will favour the creation of ammonia since the forward reaction happens with a decrease in volume. At a pressure of 200×105Pa (200 atmospheres), the reaction is normally carried out.
  3. Catalyst: The reaction rate is relatively slow, at roughly 700K. Iron oxide is used as a catalyst, along with a minor amount of K2O and Al2O3. The addition of molybdenum as a promoter improves the efficiency of the catalyst.

Haber’s technique compresses a mixture of N2 and H2 in a 1:3 molar ratio to roughly 200-atmosphere pressure. After cooling, the compressed gases are transported through a soda-lime tower to remove moisture and carbon dioxide. These are then fed into a catalyst chamber containing iron oxide, a small amount of k2O, and Al2O3. When the two gases combine to make ammonia, the chamber is heated electrically to a temperature of 700K. Because the process is exothermic, the heat generated keeps the temperature at the desired level, and no additional electrical heating is necessary.

The gases seeping from the chamber contain around 15–20 % ammonia, with the rest being nitrogen and hydrogen with no reaction. They pass via the condensing pipe, which liquefies the ammonia in the receptor and collects it. The unreacted gases are pumped back to the compression pump, where they are mixed with a new gas combination.

Ammonia (NH₃) is a colorless gas with a sharp, pungent odor. It is a compound of nitrogen and hydrogen and plays a crucial role in both the industrial sector and biological processes.

The Haber Process

Uses of Ammonia

The following are some of the many uses for ammonia:

  • In Ostwald’s nitric acid synthesis process.
  • In the manufacturing of sodium carbonate, the Solvay process is used.
  • It’s used in the production of rayon and urea.
  • Ammonium sulphate, ammonium nitrate, urea, diammonium phosphate, and other fertilizers are produced.
  • In ice plants as a refrigerant.
  • Furniture and glass surfaces can be cleaned with it.
  • In the laboratory, it is employed as a solvent and as a reagent.

Frequently Asked Questions on Ammonia

What is the Chemical Formula of Ammonia?

The chemical symbol for ammonia is NH3​. This represents a molecule of ammonia consisting of one nitrogen atom (N) and three hydrogen atoms (H).

What is the Structure of Ammonia?

The structure of ammonia (NH₃) is trigonal pyramidal. This molecule consists of one nitrogen atom (N) at the center with three hydrogen atoms (H) symmetrically spaced around it.

What are Properties of Ammonia?

Ammonia is a colourless gas with a distinctive pungent ammoniacal odour. It is lighter than air and may easily liquefy at room temperature when subjected to a pressure of 8 to 10 atmospheres. Under one atmosphere pressure, its boiling point is –33.5C(239.6K). It serves as a Lewis foundation.

What is the Preparation Method of Ammonia?

Haber’s technology is used to produce ammonia on a commercial basis.

N2 (g) + 3H2 ⇌ NH3 (g)  ; ΔH=–92.4kJ/mol

This reaction is carried out in the presence of iron oxide as a catalyst with a little amount of K2O and Al2O3 at a temperature of 700K and a pressure of 200×105Pa or 200 atmospheres. Molybdenum is utilised as a promoter to improve the catalyst’s efficiency.

What are the Uses of Ammonia?

Ammonia is used as:

  1. In the production of nitric acid by Ostwald’s process, sodium carbonate by Solvay’s process, and rayon and urea by Solvay’s process.
  2. In the production of fertilizers such ammonium sulphate, ammonium nitrate, urea, and diammonium phosphate, among others.
  3. In ice plants as a refrigerant.
  4. As a surface cleaner for furniture and glass.
  5. In the laboratory, it is utilised as a solvent and as a reagent.

What Type of Reaction is the Synthesis of Ammonia by Haber’s process?

Haber’s technique produces ammonia through a reversible, exothermic reaction that results in a drop in volume. We hope you found this ammonia post useful. If you have any questions, please leave a comment below and we will respond as soon as possible.

Er. Neeraj K.Anand is a freelance mentor and writer who specializes in Engineering & Science subjects. Neeraj Anand received a B.Tech degree in Electronics and Communication Engineering from N.I.T Warangal & M.Tech Post Graduation from IETE, New Delhi. He has over 30 years of teaching experience and serves as the Head of Department of ANAND CLASSES. He concentrated all his energy and experiences in academics and subsequently grew up as one of the best mentors in the country for students aspiring for success in competitive examinations. In parallel, he started a Technical Publication "ANAND TECHNICAL PUBLISHERS" in 2002 and Educational Newspaper "NATIONAL EDUCATION NEWS" in 2014 at Jalandhar. Now he is a Director of leading publication "ANAND TECHNICAL PUBLISHERS", "ANAND CLASSES" and "NATIONAL EDUCATION NEWS". He has published more than hundred books in the field of Physics, Mathematics, Computers and Information Technology. Besides this he has written many books to help students prepare for IIT-JEE and AIPMT entrance exams. He is an executive member of the IEEE (Institute of Electrical & Electronics Engineers. USA) and honorary member of many Indian scientific societies such as Institution of Electronics & Telecommunication Engineers, Aeronautical Society of India, Bioinformatics Institute of India, Institution of Engineers. He has got award from American Biographical Institute Board of International Research in the year 2005.

CBSE Class 11 Chemistry Syllabus

CBSE Class 11 Chemistry Syllabus is a vast which needs a clear understanding of the concepts and topics. Knowing CBSE Class 11 Chemistry syllabus helps students to understand the course structure of Chemistry.

Unit-wise CBSE Class 11 Syllabus for Chemistry

Below is a list of detailed information on each unit for Class 11 Students.

UNIT I – Some Basic Concepts of Chemistry

General Introduction: Importance and scope of Chemistry.

Nature of matter, laws of chemical combination, Dalton’s atomic theory: concept of elements,
atoms and molecules.

Atomic and molecular masses, mole concept and molar mass, percentage composition, empirical and molecular formula, chemical reactions, stoichiometry and calculations based on stoichiometry.

UNIT II – Structure of Atom

Discovery of Electron, Proton and Neutron, atomic number, isotopes and isobars. Thomson’s model and its limitations. Rutherford’s model and its limitations, Bohr’s model and its limitations, concept of shells and subshells, dual nature of matter and light, de Broglie’s relationship, Heisenberg uncertainty principle, concept of orbitals, quantum numbers, shapes of s, p and d orbitals, rules for filling electrons in orbitals – Aufbau principle, Pauli’s exclusion principle and Hund’s rule, electronic configuration of atoms, stability of half-filled and completely filled orbitals.

UNIT III – Classification of Elements and Periodicity in Properties

Significance of classification, brief history of the development of periodic table, modern periodic law and the present form of periodic table, periodic trends in properties of elements -atomic radii, ionic radii, inert gas radii, Ionization enthalpy, electron gain enthalpy, electronegativity, valency. Nomenclature of elements with atomic number greater than 100.

UNIT IV – Chemical Bonding and Molecular Structure

Valence electrons, ionic bond, covalent bond, bond parameters, Lewis structure, polar character of covalent bond, covalent character of ionic bond, valence bond theory, resonance, geometry of covalent molecules, VSEPR theory, concept of hybridization, involving s, p and d orbitals and shapes of some simple molecules, molecular orbital theory of homonuclear diatomic molecules(qualitative idea only), Hydrogen bond.

UNIT V – Chemical Thermodynamics

Concepts of System and types of systems, surroundings, work, heat, energy, extensive and intensive properties, state functions. First law of thermodynamics – internal energy and enthalpy, measurement of U and H, Hess’s law of constant heat summation, enthalpy of bond dissociation, combustion, formation, atomization, sublimation, phase transition, ionization, solution and dilution. Second law of Thermodynamics (brief introduction)
Introduction of entropy as a state function, Gibb’s energy change for spontaneous and nonspontaneous processes.
Third law of thermodynamics (brief introduction).

UNIT VI – Equilibrium

Equilibrium in physical and chemical processes, dynamic nature of equilibrium, law of mass action, equilibrium constant, factors affecting equilibrium – Le Chatelier’s principle, ionic equilibrium- ionization of acids and bases, strong and weak electrolytes, degree of ionization,
ionization of poly basic acids, acid strength, concept of pH, hydrolysis of salts (elementary idea), buffer solution, Henderson Equation, solubility product, common ion effect (with illustrative examples).

UNIT VII – Redox Reactions

Concept of oxidation and reduction, redox reactions, oxidation number, balancing redox reactions, in terms of loss and gain of electrons and change in oxidation number, applications of redox reactions.

UNIT VIII – Organic Chemistry: Some basic Principles and Techniques

General introduction, classification and IUPAC nomenclature of organic compounds. Electronic displacements in a covalent bond: inductive effect, electromeric effect, resonance and hyper conjugation. Homolytic and heterolytic fission of a covalent bond: free radicals, carbocations, carbanions, electrophiles and nucleophiles, types of organic reactions.

UNIT IX – Hydrocarbons

Classification of Hydrocarbons
Aliphatic Hydrocarbons:
Alkanes – Nomenclature, isomerism, conformation (ethane only), physical properties, chemical reactions.
Alkenes – Nomenclature, structure of double bond (ethene), geometrical isomerism, physical properties, methods of preparation, chemical reactions: addition of hydrogen, halogen, water, hydrogen halides (Markovnikov’s addition and peroxide effect), ozonolysis, oxidation, mechanism of electrophilic addition.
Alkynes – Nomenclature, structure of triple bond (ethyne), physical properties, methods of preparation, chemical reactions: acidic character of alkynes, addition reaction of – hydrogen, halogens, hydrogen halides and water.

Aromatic Hydrocarbons:

Introduction, IUPAC nomenclature, benzene: resonance, aromaticity, chemical properties: mechanism of electrophilic substitution. Nitration, sulphonation, halogenation, Friedel Craft’s alkylation and acylation, directive influence of functional group in monosubstituted benzene. Carcinogenicity and toxicity.

To know the CBSE Syllabus for all the classes from 1 to 12, visit the Syllabus page of CBSE. Meanwhile, to get the Practical Syllabus of Class 11 Chemistry, read on to find out more about the syllabus and related information in this page.

CBSE Class 11 Chemistry Practical Syllabus with Marking Scheme

In Chemistry subject, practical also plays a vital role in improving their academic scores in the subject. The overall weightage of Chemistry practical mentioned in the CBSE Class 11 Chemistry syllabus is 30 marks. So, students must try their best to score well in practicals along with theory. It will help in increasing their overall academic score.

CBSE Class 11 Chemistry Practical Syllabus

The experiments will be conducted under the supervision of subject teacher. CBSE Chemistry Practicals is for 30 marks. This contribute to the overall practical marks for the subject.

The table below consists of evaluation scheme of practical exams.

Evaluation SchemeMarks
Volumetric Analysis08
Salt Analysis08
Content Based Experiment06
Project Work04
Class record and viva04
Total30

CBSE Syllabus for Class 11 Chemistry Practical

Micro-chemical methods are available for several of the practical experiments. Wherever possible such techniques should be used.

A. Basic Laboratory Techniques
1. Cutting glass tube and glass rod
2. Bending a glass tube
3. Drawing out a glass jet
4. Boring a cork

B. Characterization and Purification of Chemical Substances
1. Determination of melting point of an organic compound.
2. Determination of boiling point of an organic compound.
3. Crystallization of impure sample of any one of the following: Alum, Copper Sulphate, Benzoic Acid.

C. Experiments based on pH

1. Any one of the following experiments:

  • Determination of pH of some solutions obtained from fruit juices, solution of known and varied concentrations of acids, bases and salts using pH paper or universal indicator.
  • Comparing the pH of solutions of strong and weak acids of same concentration.
  • Study the pH change in the titration of a strong base using universal indicator.

2. Study the pH change by common-ion in case of weak acids and weak bases.

D. Chemical Equilibrium
One of the following experiments:

1. Study the shift in equilibrium between ferric ions and thiocyanate ions by increasing/decreasing the concentration of either of the ions.
2. Study the shift in equilibrium between [Co(H2O)6] 2+ and chloride ions by changing the concentration of either of the ions.

E. Quantitative Estimation
i. Using a mechanical balance/electronic balance.
ii. Preparation of standard solution of Oxalic acid.
iii. Determination of strength of a given solution of Sodium hydroxide by titrating it against standard solution of Oxalic acid.
iv. Preparation of standard solution of Sodium carbonate.
v. Determination of strength of a given solution of hydrochloric acid by titrating it against standard Sodium Carbonatesolution.

F. Qualitative Analysis
1) Determination of one anion and one cation in a given salt
Cations‐ Pb2+, Cu2+, As3+, Al3+, Fe3+, Mn2+, Ni2+, Zn2+, Co2+, Ca2+, Sr2+, Ba2+, Mg2+, NH4 +
Anions – (CO3)2‐ , S2‐, NO2 , SO32‐, SO2‐ , NO , Cl , Br, I‐, PO43‐ , C2O2‐ ,CH3COO
(Note: Insoluble salts excluded)

2) Detection of ‐ Nitrogen, Sulphur, Chlorine in organic compounds.

G) PROJECTS
Scientific investigations involving laboratory testing and collecting information from other sources.

A few suggested projects are as follows:

  • Checking the bacterial contamination in drinking water by testing sulphide ion
  • Study of the methods of purification of water.
  • Testing the hardness, presence of Iron, Fluoride, Chloride, etc., depending upon the regional
    variation in drinking water and study of causes of presence of these ions above permissible
    limit (if any).
  • Investigation of the foaming capacity of different washing soaps and the effect of addition of
    Sodium carbonate on it.
  • Study the acidity of different samples of tea leaves.
  • Determination of the rate of evaporation of different liquids Study the effect of acids and
    bases on the tensile strength of fibres.
  • Study of acidity of fruit and vegetable juices.

Note: Any other investigatory project, which involves about 10 periods of work, can be chosen with the approval of the teacher.

Practical Examination for Visually Impaired Students of Class 11

Below is a list of practicals for the visually impaired students.

A. List of apparatus for identification for assessment in practicals (All experiments)
Beaker, tripod stand, wire gauze, glass rod, funnel, filter paper, Bunsen burner, test tube, test tube stand,
dropper, test tube holder, ignition tube, china dish, tongs, standard flask, pipette, burette, conical flask, clamp
stand, dropper, wash bottle
• Odour detection in qualitative analysis
• Procedure/Setup of the apparatus

B. List of Experiments A. Characterization and Purification of Chemical Substances
1. Crystallization of an impure sample of any one of the following: copper sulphate, benzoic acid
B. Experiments based on pH
1. Determination of pH of some solutions obtained from fruit juices, solutions of known and varied
concentrations of acids, bases and salts using pH paper
2. Comparing the pH of solutions of strong and weak acids of same concentration.

C. Chemical Equilibrium
1. Study the shift in equilibrium between ferric ions and thiocyanate ions by increasing/decreasing
the concentration of eitherions.
2. Study the shift in equilibrium between [Co(H2O)6]2+ and chloride ions by changing the
concentration of either of the ions.

D. Quantitative estimation
1. Preparation of standard solution of oxalic acid.
2. Determination of molarity of a given solution of sodium hydroxide by titrating it against standard
solution of oxalic acid.

E. Qualitative Analysis
1. Determination of one anion and one cation in a given salt
2. Cations – NH+4
Anions – (CO3)2-, S2-, (SO3)2-, Cl-, CH3COO-
(Note: insoluble salts excluded)
3. Detection of Nitrogen in the given organic compound.
4. Detection of Halogen in the given organic compound.

Note: The above practicals may be carried out in an experiential manner rather than recording observations.

We hope students must have found this information on CBSE Syllabus useful for their studying Chemistry. Learn Maths & Science in interactive and fun loving ways with ANAND CLASSES (A School Of Competitions) App/Tablet.

Frequently Asked Questions on CBSE Class 11 Chemistry Syllabus

Q1

How many units are in the CBSE Class 11 Chemistry Syllabus?

There are 9 units in the CBSE Class 11 Chemistry Syllabus. Students can access various study materials for the chapters mentioned in this article for free at ANAND CLASSES (A School Of Competitions).

Q2

What is the total marks for practicals examination as per the CBSE Class 11 Chemistry Syllabus?

The total marks for the practicals as per the CBSE Class 11 Chemistry Syllabus is 30. It includes volumetric analysis, content-based experiment, salt analysis, class record, project work and viva.

Q3

Which chapter carries more weightage as per the CBSE Syllabus for Class 11 Chemistry?

The organic chemistry chapter carries more weightage as per the CBSE Syllabus for Class 11 Chemistry.