Hydrogen

Question 1
CBSEENCH11006814

How does H+ ion exist in water?

Solution
space space straight H to the power of plus space ion space exists space in space water space as space straight H subscript 3 straight O to the power of plus
Question 2
CBSEENCH11006815

Why does hydrogen occur in a diatomic form rather than in a monoatomic form under normal conditions?

Solution

A molecule of hydrogen is formed by the combination of two atoms of hydrogen with one electron each present in the 1s orbital. hydrogen (1s1) has one electron less than the stable inert gas configuration (He;1s2) and therefore it shares its single electron with an electron of another hydrogen atom to form a stable diatomic molecule. Thus two electrons are present in the hydrogen molecule and both will be accommodated in the molecular orbital of lowest energy. The bond order of H2 is +1. The positive value of bond order indicates that the H2 (diatomic) molecules are stable.

Question 3
CBSEENCH11006816

Give one example in which hydrogen acts as an oxidising agent.

Solution
2Na + H2 → 2NaH
Here, hydrogen acts as the oxidising agent.
Question 4
CBSEENCH11006817

Give laboratory Preparation of Dihydrogen ?

Solution

It can also be prepared by the reaction of zinc with aqueous alkali.
Zn + 2NaOH → Na2ZnO2 + H2

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