Explore topic-wise InterviewSolutions in .

1. In these, hydrogen bonding is very important. Often the water molecules serve to fill in the interstices and bind together structure.

2. A specific example is CuSO₄ . 5H₂O.

3. Although there are five water molecules for every divalent copper ion, only four are coordinated to the cation, it’s six-coordination being completed from sulphate anions. The fifth water molecule is held in place of hydrogen bonds, O – H – O, between it and two coordinated water molecules and then coordinate sulphate anion. 

4. Water forms hydrated salts during crystallization.

Examples, Na₂CO₃ . 10H₂O, FeSO₄ .7H₂O. 

5. The water present in the hydrates is called as water of hydration.

• Gas hydrates in which the guest molecules are not bonded chemically but retained by the structure of host is called Clatharates. 
• Water forms clatharate hydrates, e.g., methane hydrate (CH₄20H₂O) which arc a type of ice that will bum when a lit match is held to it. 
• The structure of methane hydrate is made of linked polyhedra that contains 20 hydrogen bonded water molecules forming a cage in which methane molecule is trapped. 
• Deposits of methane clatharates occur naturally in deep sea bed.
• Hydrates are commonly obtained when water is frozen in presence of a gas such as argon, methane, etc. 
• Most gases form hydrates under high pressure.

Uses of Hydrogen:

It used as a reducing agent. In the manufacture of vanaspati fat, ammonia, metal hydrides, methanol, fertilizers such as urea etc. 

In the manufacture of synthetic petrol. 

In the atomic hydrogen torch and oxy hydrogen torches for cutting and welding. Dihydrogen is dissociated with the help of an electric arc and the hydrogen atoms produced are allowed to recombine on the surface to be welded. High temperature of about 4000 k is generated. 

In the fuel cell for generating electrical energy. 

Uses of hydrogen peroxide :

(1) For bleaching silk, wool, hair and leather 

(2) As rocket fuel 

It must be kept in wax lined coloured bottles because the rough glass surface causes its decomposition. 

A small amount of phosphoric acid, glycerol or acetanilide is generally added which retard the decomposition of H₂O₂. These are also called negative catalysts.

(i) HCl 

(ii) NaH

Carbon monoxide and hydrogen. 

It means that 1 ml of H₂O₂ will give 10 ml of oxygen at N.T.P. 

It is prepared by electrolysis of heavy water 

(D₂O) 2D₂O → 2D₂ + O₂

The pH value of water is 7.

H₂ is combustible in nature. Therefore it may react with oxygen violently. Thus it is not used 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.

Dihydrogen gas is combustible in nature. Therefore, it may react with oxygen highly violently. Thus, it is not used in balloons. 

The addition of H₂ to an unsaturated compound in the presence of Ni or Pt is called Hydrogenation. 

CH₂=CH₂+H₂---Ni ---> CH₃-CH₃

 1 like alkali metals hydrogen also has one electron in its valence shell 

2 like alkali metals hydrogen loses its only electron to form proton(H+) 

3 like alkalis metals hydrogen exhibits an oxidation state of +1 in its compounds 

4 When an aqueous solution of HCl is electrolysed H₂ is librated at the cathode in the same way as alkali metals are librated at the cathode during the electrolysis of their fused halides.

Hydrogen is a highly inflammable gas which bums with a ‘pop’ sound and blue flame and forms water.

H₂ is relatively inert at room temperature due to the high H – H bond enthalpy.

Granulated zinc contains traces of copper as an impurity which acts as a catalyst. It also prevents the deposition of the gas on zinc.

(i) High bond dissociation energy of H-H bond 

(ii) Hydrogen molecule dissociate into atomic hydrogen at very high temperature (4000K) 

(iii) Because of least electronegativity difference.