This set of Chemistry Assessment Questions for Class 11 focuses on “Hydrogen – Heavy Water & D2O”.
1. Which of the following is a trace or compound?
c) Heavy water
d) Normal water
Explanation: One of the main important use of heavy water is, it is used as a tracer compound in order to study the mechanism of many reactions, this is because of the deuterium present in heavy water which enables to study the mechanism.
2. Is there any difference in heavy water compared with normal Water?
c) Cannot say
Explanation: Due to the presence of the isotope of hydrogen that is deuterium in heavy water there are many changes in the nuclear properties. Also due to a slight increase in mass the physical properties and chemical properties also change.
3. By how much percent is heavy water’s density greater than that of normal Water?
Explanation: The density of heavy water is 11 % greater than that of normal water, this happens because 89% of water or heavy waters mass comes from the single oxygen. The above thing is valid only when hydrogen peroxide is in its pure form.
4. What is Semi-heavy water?
Explanation: Semi-heavy water is the molecule which contains one atom of Hydrogen, an atom of hydrogen isotope that is deuterium and one atom of oxygen. Thus it is known as semi-heavy water. Its density is given as 1.054
5. Tritiated water is same as heavy water.
Explanation: Heavy water is formed by two atoms of deuterium and one atom of oxygen, whereas tritiated water is formed by two atoms of tritium and one atom of Oxygen. Heavy water is not radioactive while tritiated water is Radioactive; therefore the above statement is false.
6. What is heavy water?
Explanation: Heavy water is given by its chemical formula as D2O, it was discovered by Urey in the year 1932 and it can be prepared by exhaustive electrolysis of ordinary water using Nickel electrodes. It is generally colorless, odorless and tasteless liquid.
7. What does D represent in heavy water?
Explanation: The chemical formula of heavy water is D2O, where D represents deuterium and O represents oxygen. Two atoms of deuterium and one atom of Oxygen combine to form heavy water (D2O).
8. What is a result of the reaction of heavy water with sodium?
a) Formation of Hydrogen
b) Formation of sodium
c) Formation of sodium hydroxide
d) Sodium deuteroxide
Explanation: When one mole of heavy water reacts with one mole of sodium, it results in the formation of 1 mole of sodium deuteroxide and half a mole of deuterium it is represented chemically as 1D2O + 1Na → 1NaOD + 1/2D2.
9. What is the chemical formula of deuterosulphuric acid?
Explanation: The formation of deuterosulphuric acid occurs when 1 mole of heavy water (D2O) reacts with one mole of sulfur trioxide (SO3). The chemical formula of deuterosulphuric acid is given by D2SO4.
10. Heavy water is called as a moderator.
Explanation: Yes, heavy water is called a moderator because it is used in nuclear reactors to slow down the speed of neutrons. Hence the above statement that ‘ heavy water is called as a moderator ’is considered to be true.
Sanfoundry Global Education & Learning Series – Chemistry – Class 11.
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