Heavy Water – Uses, Properties, Types, Preparation, Reactions (D2O)

February 11, 2025December 19, 2024 by Neeraj Anand, Param Anand

What Is Heavy Water?

Heavy water is a compound that is made up of oxygen and deuterium, a heavier isotope of hydrogen which is denoted by ‘²H’ or ‘D’. Heavy water is also called deuterium oxide and is denoted by the chemical formula D₂O.

It has a greater molar mass than regular water since the atomic mass of deuterium is greater than that of protium. This causes heavy water (D₂O) to have slightly different chemical and physical properties when compared to H₂O.

Properties of Heavy Water

Heavy Water (Deuterium Oxide)	D₂O
Molecular Mass	20.02 grams/mole
Density	1.107 g/mL
Dipole Moment	1.87 D
Melting Point	3.82^oC
Boiling Point	101.4^oC

Physical Properties

Heavy water has a colourless appearance at STP.
At room temperature, it exists as an odourless liquid.
Since the density of D₂O is approximately 11% greater than that of H₂O, an ice cube made of deuterium oxide will sink in normal water.
Heavy water forms a homogeneous mixture when mixed with normal water.

Chemical Properties

The isotopes of hydrogen exhibit different chemical behaviour because of the differences in their atomic masses.
The changes to the solvent properties of water due to the presence of high quantities of deuterium can adversely affect biological systems.
Normal water dissociates to a further extent when compared to heavy water.
At a given temperature, the concentration of D⁺ ions in a D₂O sample is generally lower than the concentration of H⁺ ions in an H₂O sample.

Methods of Preparation

Heavy water is prepared by the prolonged electrolysis of water containing alkali.

Electrolyte: Water containing NaOH
Cathode: Steel vessel
Anode: Nickel sheet with holes

Electrolysis is continued for seven alkalies that are neutralised by the passage of CO₂ gas. The leftover product is heavy water. Some important features of heavy water are listed below:

The nucleus of a deuterium atom holds one proton and one neutron, making it roughly twice as heavy as protium (the isotope of hydrogen present in normal water, denoted by ¹H).
Approximately 89% of the molecular mass of a water molecule is attributed to oxygen. Therefore, the molecular mass of D₂O is not substantially greater than that of H_2.
The density of heavy water is ~11% higher than that of normal water.
The deuterium-oxygen bond in D₂O is stronger than the protium-oxygen bond in H_2.
D₂O is not radioactive in nature because the deuterium atom does not undergo radioactive decay.
High doses of heavy water can prove toxic to many organisms.

The first production of deuterium oxide was in the year 1932. It is used as a neutron moderator and coolant in pressurised heavy water reactors (PHWR). The term ‘heavy water’ typically refers to D₂O. However, other “heavy” forms of water exist as well.

Types of Heavy Water

Semi-Heavy Water (HDO)

This form of heavy water is denoted by the formula HDO and is made up of one protium, one deuterium, and one oxygen atom.
Water molecules tend to exchange hydrogen atoms with each other. This implies that HDO can be found in samples of water containing both protium and deuterium.
A water sample containing an equal ratio of protium and deuterium consists of 50% semi-heavy water, 25% normal water, and 25% heavy water.
In this sample, there exists a dynamic equilibrium between HDO, D₂O, and H_2.

Heavy-Oxygen Water

Water containing heavier isotopes of water, such as ¹⁷O and ¹⁸O, is referred to as heavy-oxygen water.
Its density is higher than regular water, due to which it is categorised as a form of heavy water.
Heavy-oxygen water containing the ¹⁸O isotope of oxygen is used in the production of the ¹⁸F isotope of fluorine. It is also used in radiotracers and radiopharmaceuticals.

Tritiated Water (T₂O)

It is a radioactive form of water that contains tritium (denoted by T or ³H) instead of protium.
It is commonly called super-heavy water and is denoted by the formula T_2.
Tritiated water can be used to determine the total volume of water in a body.
The molar mass of T₂O is 22.03 grams per mole, and its density is 1.85 g/mL.

Some Important Reactions of Heavy Water

Electrolysis: 2D₂O → 2D₂ (Deuterium)+ O₂
Reactions with Metals: 2Na + 2D₂O → 2NaOD (Sodium Deuteroxide) + D₂
Reactions with Non-Metals: D₂O + Cl₂ → DCl + DOCl
Reactions with Metal Oxide: MgO + D₂O → Mg(OD)₂
Reactions with Non-Metal Oxides: SO₃ + D₂O → D₂SO₄ (Deutero sulphuric acid)
Reactions with Magnesium Nitride: Mg₃N₂ + 6D₂O → 3Mg(OD)₂ + 2ND₃ (Deutero Ammonia)
Reactions with Calcium Phosphide: Ca₃P₂+6D₂O → 3Ca(OD)₂+2PD₃ (Deutero Phosphide)
Reactions with Calcium Carbide: CaC₂ + 2D₂O → Ca(OD)₂+ C2D₂(Deutero Acetylene)
Reactions with Aluminium Carbide: Al₄C₃ + 12D₂O → 4Al(OD)₃ + 3CD₄ (Deutero methane)

Some other uses include,

Heavy water is used in nuclear magnetic resonance spectroscopy.
It is used as a moderator in certain types of nuclear reactors.
It is used in the medical field to test the metabolic rate of human beings.

Uses of Heavy Water

As mentioned earlier, deuterium oxide is an integral part of heavy water nuclear reactors, where it is used as a coolant and as a neutron moderator. Some other important applications of heavy water are listed below:

Heavy water is used for the preparation of deuterium.
It is used as a tracer to study the mechanism of respiration and photosynthesis.
D₂O is used in NMR (nuclear magnetic resonance) spectroscopy, which is used to observe the magnetic fields around the nuclei of atoms.
Isotopologues of many organic compounds are prepared with the help of deuterium oxide.
Heavy water is often used instead of normal water in IR (infrared) spectroscopy.
It is used as a moderator in the nuclear reactor to slow down the neutrons. Since it can slow down the fast-moving neutrons, they can react with the ²³⁵U isotope instead of the ²³⁸U isotope.
The metabolic rate in humans and animals is tested with the help of a mixture of D₂O and heavy-oxygen water.
Tritium, the active substance used in controlled nuclear fusion reactions, is formed when the deuterium present in heavy water captures a neutron.

Can You Drink Heavy Water? Is It Dangerous?

Most of the time, when we talk about heavy water, we tend to relate it to nuclear reactors and radioactive materials. However, pure heavy water is not radioactive and not so harmful if ingested by human beings in small quantities. It is only harmful or dangerous if the water is consumed in large quantities or if heavy water is taken for a long duration of time. Poisoning may occur and lead to symptoms like dizziness and loss of blood pressure.

Frequently Asked Questions (FAQs)

What is the chemical formula of heavy water?

D₂O is the formula of heavy water.

What is the boiling point of heavy water?

101.4° is the boiling point of heavy water. It is slightly higher than water.

How is heavy water prepared?

Heavy water is prepared by electrolysis of alkali water.

What is the electrolyte, anode and cathode used in heavy water preparation?

Electrolyte: Alkali water
Anode: Nickel sheet with holes
Cathode: Steel vessel.

What is the radioactive form of water?

T₂O is the radioactive form of water.

Neeraj Anand, Param Anand

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.

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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 Scheme	Marks
Volumetric Analysis	08
Salt Analysis	08
Content Based Experiment	06
Project Work	04
Class record and viva	04
Total	30

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‐ , S^2‐, NO₂^‐ , SO₃^2‐, SO^2‐ , NO ^‐ , Cl^‐ , Br^‐, I‐, PO₄^3‐ , 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

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).

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.

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.