Question

IIeavy water is qualified as heavy water because it is (1) a heavy liquid (2) an oxide of heavicr isotopc of oxygen (3) an oxidc of deutcrium (4) denser than water

Short answer

The correct answer is (3) an oxide of deuterium.

Step-by-step solution

- Understanding the Term 'Heavy Water'

Heavy water is chemically known as D2O. It is a form of water where the hydrogen atoms (H) are replaced by deuterium (D), which is an isotope of hydrogen.

- Examination of Options

Let's examine each option:(1) 'a heavy liquid' - This is a vague description that does not explain the chemical nature of heavy water.(2) 'an oxide of a heavier isotope of oxygen' - Heavy water is not related to isotopes of oxygen; it relates to isotopes of hydrogen.(3) 'an oxide of deuterium' - Deuterium is indeed a heavier isotope of hydrogen, and heavy water is an oxide of deuterium.(4) 'denser than water' - While heavy water is denser than regular water due to deuterium, this description is also not specific to its chemical nature.

- Selection of Correct Option

Based on the explanations above, the correct and most accurate description of heavy water is option (3) 'an oxide of deuterium'.

Key concepts

Deuterium

Deuterium is one of the isotopes of hydrogen. While the most common form of hydrogen has just one proton in its nucleus, deuterium includes one proton and one neutron.
This makes deuterium doubly heavy compared to regular hydrogen. The presence of an additional neutron gives deuterium a mass number of 2.
Because of its extra neutron, deuterium has different properties compared to regular hydrogen, which is crucial in the formation of heavy water.
Deuterium is represented by the symbol D or ^{2}H in chemical formulas.

Isotopes of Hydrogen

Hydrogen has three isotopes: protium, deuterium, and tritium.
Protium ( ^{1}H) is the most abundant isotope, comprising over 99% of naturally occurring hydrogen. It has one proton and no neutrons.
Deuterium ( ^{2}H) is the second isotope, containing one neutron and one proton. It is present in small amounts in natural hydrogen, about 0.0156%.
Tritium ( ^{3}H), the rarest, contains two neutrons and one proton. Tritium is radioactive and decays over time, making it much less common.
Isotopes have nearly identical chemical behaviors but different physical properties due to their varying masses. This difference in mass is why deuterium forms heavy water (D2O) instead of regular water (H2O).

D2O

D2O, commonly known as heavy water, is water where both hydrogen atoms are replaced with deuterium.
The chemical composition of D2O makes it about 10% denser than regular H2O. This increased density is due to the extra neutron in each deuterium atom, which doubles the mass compared to normal hydrogen.
Heavy water is essential in various scientific applications. For example, it is used as a neutron moderator in nuclear reactors, helping to sustain nuclear fission reactions.
While heavy water is chemically similar to regular water, its physical properties, such as higher boiling and melting points, make it distinctive.
It also plays a critical role in certain types of scientific research and industrial processes.