CHEMISTRY Class XI Chapter : Hydrogen Free Notes
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| CHEMISTRY Class XI Chapter : Hydrogen Free Notes |
Which isotope of hydrogen (i) does not contain neutron? (ii) is radioactive?
Ans. (i) Protium (ii) Tritium
Give the main characteristics of isotopes.
Since, the isotopes have the same electronic configuration, they have almost the same chemical properties. The only difference is in their rates of reactions, mainly due to their different enthalpy of bond dissociation. However, in physical properly of these isotopes differ considerably due to their large mass differences.
What is syn-gas?
Mixture of CO and H2 is used for the synthesis of methanol and a number of hydrocarbons it is also called synthesis gas or ‘syngas’
Give the main characteristics of isotopes.
Since, the isotopes have the same electronic configuration, they have almost the same chemical properties. The only difference is in their rates of reactions, mainly due to their different enthalpy of bond dissociation. However, in physical properly of these isotopes differ considerably due to their large mass differences.
Why is dihydrogen gas not preferred in balloons?
Dihydrogen is the lightest gas and should have been used in balloons. But it is not preferred due to its highly combustible nature.
What is the pH of water?
The pH value of water is 7.
Why is dihydrogen used an fuel cells for generating electrical energy?
Because it does not produce any pollution and releases greater energy per unit mass of fuel in comparison to gasoline or any other fuel.
What is understood by hydrogenation?
Hydrogenation is used for the conversion of polyunsaturated oils into edible fats.
Which fuel is used as a rocket fuel?
Dihydrogen is used as a rocket fuel in space research.
Name the categories into which hydrides are categorized.
The hydrides are classified into three categories -
(i)Ionic or saline or salt like hydrides.
(ii) Covalent or molecular hydrides
(iii) Metallic or non-stoichiometric hydrides.
What are hydrides?
Dihydrogen under certain reaction conditions combines with almost all elements, except noble gases, to form binary compounds, called hydrides.
Give an example of each of an ionic hydride and a covalent hydride.
Ionic hydride: LiH, NaH Covalent hydride CH4, NH3 and H2O
Give an example of electron – deficient hydride
Diborane.
8. What is the geometry of the compound formed by group 14 to form molecular hydride?
Tetrahedral in structure.
9. What are the characteristic features of ionic or saline hydrides?
The ionic hydrides are crystalline, non – volatile non – conducting in solid state. However their melts conduct electricity.
10. Which gas is produced on electrolysis of ionic hydride?
Dihydrogen gas is produced at the anode on electrolysis of ionic hydride.
Why is ice less dense then water and what kind of attractive forces must be overcome to melt ice?
The structure of ice is an open structure having a number of vacant spaces. Therefore, the density of ice is less than water. When ice melts the hydrogen bonds are broken and the water molecules go in between the vacant spaces. As a result, the structure of liquid water is less open than structure of ice. Thus ice is less dense than water.
Why is water an excellent solvent for ionic or polar substances?
Water is a polar solvent with a high dielectric constant. Due to high dielectric constant of water the force of attraction between cation and anion gets weakened. Thus water molecules are able to remove ions from the lattice site using in dipole forces easily.
How many hydrogen – bonded water molecule are associated in CuSO4. 5H2O?
Only one water molecule, which is outside the brackets (coordinator spheres), is hydrogen bonded. The other four molecules of water are co-ordinated.
What do you mean by 100 volume of hydrogen peroxide?
It means that one milliliter of 30% H2O2 solution will give 100v of oxygen at STP
Hydrogen peroxide acts as oxidizing agent as well as a reducing agent. Why?
Hydrogen peroxide can act as an oxidizing agent because it readily decomposes to evolve oxygen and also take up oxygen from water.
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