RBSE Class 11 Chemistry Notes Chapter 9 Hydrogen

These comprehensive RBSE Class 11 Chemistry Notes Chapter 9 Hydrogen will give a brief overview of all the concepts.

RBSE Class 11 Chemistry Chapter 9 Notes Hydrogen

→ Isotopes of Hydrogen: Hydrogen has three isotopes, namely: protium (₁H), deuterium (D or ₁²H) and tritium (T or ₁³H).

→ Oxidation Step: This is the first step in Lane’s method for production of hydrogen. In this, steam is passed over red hot iron by which iron changes to iron oxide and hydrogen gas is also released.

→ Reduction Step: This is thfe second step in Lane’s method for production of hydrogen. In this method, steam is stopped after the formation of iron oxide and is reduced to Fe. In this process, water gas (CO + H₂) is passed.

→ Syngas: CO and H₂, known as water gas or syngas is used in synthesis of methanol and other hydrocarbons. Therefore, it is also. known as synthesis or syngas.

→ Coal Gasification: The production of syngas by coal is called coal gasification.

→ Water Gas Shift Reaction: The mixture of CO and H₂ is called water gas. In this red hot coke is heated at high temperature in the presence of catalyst by passing steam.
C + H₂O → CO + H₂

→ Adsorption of Hydrogen: Hydrogen gas is adsorbed by metals like platinum black and palladium. This is known as adsorption of hydrogen. Hydrogen gas purifies by this method because palladium is adsorbed only pure hydrogen.

→ Hydrogenation of Oil: Hydrogenation converts liquid vegetable oils into solid or semi-solid fats, such as those present in margarine. Changing the degree of saturation of the fat changes some important physical properties, such as the melting range, which is why liquid oils become semi-solid.

→ Ortho and Para Hydrogen: Ortho-hydrogen molecules are those in which the spins of both the nuclei are in the same direction. While para-hydrogen is when the spins of both the nuclei are in the opposite directions.

→ Chemical Harmonium or Singing Flame: When a flame, as of hydrogen gas or coal gas , burning within a tube is adjusted in such a way so as to set the air within the tube in vibration, it causes sound with different nodes with changing levels of air column inside the tube. This is called Chemical Harmonium or Singing Flame.

→ Ionic Hydride: These are stoichiometric compounds of dihydrogen formed with most of the s-block elements.

→ Covalent or Molecular Hydrides: Dihydrogen forms molecular hydrides with most of the p-block elements.

→ Electron Deficient Hydride: Elements of group 13 will form electron-deficient compounds or hydrides. .

→ Electron-Precise Hydride: All elements of group 14 form electron precise hydrides.

→ Electron Rich Hydrides: Elements of group 15-17 form such compounds. Electron-rich hydrides have excess electrons which are present as lone pairs.

→ Metallic or Interstitial Hydrides: These are formed when dihydrogen reacts with d-block and f-block elements.

→ Hydride Gap: Group seven, eight and nine metals do not form hydrides. This is known as hydride gap.

→ Universal Solvent: The heat of vaporisation of water is very high and it is found in liquid state. Therefore, water is a universal solvent.

→ Crystal water Molecules: If water molecules are present in definite proportion in any crystalline solid, then this form of water is known as water of crystallisation.

→ Coordinated Water: Coordinated water is water that is a ligand in a metal complex. The metal atom and the water molecules are held together by coordinate bonds.

→ Hydrogen Bonded Water: Hydrogen-bonded water is the water that is linked to some other ion by hydrogen bonding. 

→ Interstitial Water: Interstitial water is water that is present in the interstitial sites of a crystal lattice, as in hydrated RbBr.

→ Soft Water: Soft water gives lather with soap readily. It does not contain soluble calcium and magnesium salts.

→ Hard Water: Hard water does not give lather with soap. It contains soluble calcium and magnesium salts and gives precipitate with soap.

→ Calgon: Sodium hexa meta phosphate is called calgon.

→ Permutit: It is a complex molecule. Hydrated sodium aluminium silicate is called zeolite/permutit.

→ Deionised Water: Pure de-mineralised (de-ionized) water free from all soluble mineral salts.

→ Perhydrol: Perhydrol is the trade name given to a solution of hydrogen peroxide at a concentration of 30% of weight by volume(w/v) or 100 volume strength.

→ Important Facts:

• The position of hydrogen is controversial in periodic table because it shows similarities with both alkali metals and halogens.
• Hydrogen has three isotopes, protium, deuterium and tritium.
• Protium is most abundant isotope of hydrogen whereas tritium is found in least amount.
• Tritium is a radioactive element. ‘
• Mixture of CO and H₂ is called syngas.
• In laboratory, hydrogen is prepared by zinc and sulphuric acid.
• There are two nuclegr isotopes of hydrogen: ortho and para hydrogen.
• In ortho hydrogen, nucleus rotates in same direction.
• In para hydrogen, nucleus rotates in opposite directions.
• Dihydrogen combines with almost all the elements except noble gases under appropriate conditions to form hydrides.
• All the type of hydrides can be classified into three categories: Ionic or saline hydrides, Covalent or Molecular hydrides and Metallic or Non-stoichiometric hydrides.
• Water is an universal solvent.
• There are two types of water: hard water and soft water.
• Soft water gives lather with soap whereas hard water does not.
• Temporary hardness is due to bicarbonates of calcium and jnagnesium.
• In water, oxygen is in sp³ hybridised state. The geometry of water molecules is 'V’ shape or bent or angular. Its bond angle is 104.5°.
• Due to hydrogen bonding, there is atomic contraction ip water molecule.
• The density of ice is less than water. Therefore, it floats on it.
• Permanent hardness of water is due to chlorides and sulphates of calcium and magnesium.
• Permutit and ion exchange resin method is used for removal of hardness of water.
• Water free from ions is called demineralised water.
• Heavy water is used in nuclear reactors as moderator.
• Hydrogen peroxide is used for industrial purpose, bleaching and environment control etc.
• Dilute solution of hydrogen peroxide cannot be concentrated directly.
• Deuterium oxide is called heavy water.
• The structure of hydrogen peroxide is asymmetrical.
• Hydrogen peroxide acts as oxidant, reductant, colourant and weak acid.