Heavy Water vs Light Water
Water is truly a wonder molecule. It is the most abundant inorganic compound in living matter. More than 75% of our body composes of water. It is a component of cells, act as a solvent and reactant.
Light water refers to the water, H2O, which is known to all, and water is something without which we cannot live. Two hydrogens are covalently bonded to oxygen to form water. The molecule gets a bent shape to minimize the electron lone pair-bond repulsion, and the H-O-H angle is 104o. Water is a clear, colorless, tasteless, odorless liquid, and it can be in various forms such as mist, dew, snow, ice, vapor, etc. Water goes to the gas phase when it is heated above 100 oC at the normal atmospheric pressure. Water is a liquid at room temperature, although it has a low molecular weight of 18 gmol-1. The ability of water to form hydrogen bonds is the unique characteristic it has. Single water molecule can form four hydrogen bonds. Oxygen is more electronegative than hydrogen, making the O-H bonds in water polar. Because of the polarity and the ability to form hydrogen bonds, water is a powerful solvent. It is known as a universal solvent due to its capability in dissolving a large number of materials. Further, water has a high surface tension, high adhesive, cohesive forces. Water can withstand a temperature changes without going to the gas or solid form. This is known as having a high heat capacity, which in turn is important for the survival of living organisms.
In heavy water, two hydrogen atoms are replaced by deuterium atoms. This is analogous to water. Deuterium is one of the isotopes of hydrogen. There is a proton and a neutron in the nucleus of deuterium. Therefore, the mass number of it is two, and the atomic number is one. This is also known as the heavy hydrogen. Deuterium is shown as 2H. But most commonly it is represented with D. Therefore, heavy water has the molecular formula of D2O. Heavy water is transparent and has a pale blue color. Heavy water can exhibit different chemical and physical properties than the hydrogen analog of it. The molar mass of heavy water is 20.0276 g mol−1. Heavy water is used in nuclear reactors and studies of chemical and biochemical processes (used as an isotropic tracer).
What is the difference between Heavy and Light Water?
• Light water has protium isotope whereas heavy water has deuterium isotope.
• Molecular formula of light water is H2O, and the chemical formula of heavy water is D2O.
• The hydrogen atoms in light water have one proton and zero neutrons in an atomic nucleus, but each deuterium atomic nucleus in heavy water has one proton and one neutron.
• Therefore, the molar mass of heavy water is higher than that of light water. Heavy water has a molecular weight of about 20 whereas light water has about 18.
• Water is an essential component of life, but large amount of heavy water in organisms can cause death.