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Hydrogen

Short Answer Type

101. Arrange the following:
LiH, NaH and CsH in order of increasing ionic character.

1283 Views

102. Arrange the following:
H–H, D–D and F–F in order of increasing bond dissociation enthalpy.

859 Views

103. Arrange the following:

NaH, MgH₂ and H₂O in order of increasing reducing property.

1268 Views

Long Answer Type

104.

Describe the industrial uses of hydrogen which depend on:
(i) the heat liberated when it burns,
(ii) its ability to react with vegetable oil in the presence of catalyst,
(iii) its ability to unite with nitrogen.

223 Views

Short Answer Type

105. How does the atomic hydrogen or oxy-hydrogen torch function for cutting and welding purposes? Explain.

274 Views

106.

Mention some important uses of dihydrogen ?

160 Views

Long Answer Type

107. What is understood by ‘Hydrogen economy.’

156 Views

Short Answer Type

108.

How do you expect the metallic hydrides to be useful for hydrogen storage? Explain.

207 Views

109.

Give reason for the fact that liquid hydrogen is used as a fuel.

134 Views

110. Discuss the structure of H₂O molecule.

In H₂O, the oxygen is sp³ hybridised and hence has four sp³ hybrid orbitals. Two of these sp³ hybrid orbitals are half filled and hence overlap with 1s-orbitals of hydrogen to form two O-H bonds. The other two sp³ hybrid orbitals contain a lone pair of electrons each. Due to the presence of four pairs of electrons (two bond pairs and two lone pairs) around the central oxygen atom, the geometry of the molecule is expected to be tetrahedral and ZHOH bond angle should be 109°– 28'. But actually ∠HOH bond angle is 104 . 5°. This is because lone pair-lone-pair repulsions are greater than lone-pair-bond-pair repulsion which in turn are greater than bond pair-bond pair repulsions. As a result ∠HOH bond angle in water is slightly lower than the regular tetrahedron angle (109°–28'). It is 104.5° as shown.