Chemistry NCERT Exemplar Solutions Class 11th Chapter Nine

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Option (iii)

Both an oxidizing and a reducing agent

In both acidic and alkaline medium hydrogen peroxide can act as oxidizing and reducing agent.

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Option (ii)

I₂ + H₂O₂ + 2OH^–→ 2I^-+ 2H₂O + O₂

As iodine is reduced from 0 to -1.

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Option (iii)

2I^- + 2H⁺ + H₂O₂ → I₂+ 2H₂O

As the oxidation state of iodine changes from -1 to 0, this shows peroxide is oxidising in nature.

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Option (ii)

BaO₂ -8H₂O

Hydrogen peroxide is produced by acidifying barium peroxide and eliminating excess water by evaporation under low pressure.

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Option (ii)

An oxidizing agent in (A) and reducing agent in (B)

H₂O₂ acts as an oxidising agent in A as it oxidized iodine from -1 to 0, while in B it acts as reducing agent as it reduced chlorine from +1 to -1

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Option (iii)

Tritium

The tritium concentration is about one atom per 10¹⁸ atoms of protium. Of these isotopes, only tritium is radioactive and emits low energy beta particles.

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Option (iv)

CH₄

These hydrides have the required number of electrons to write their conventional Lewis structures.

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Option (ii)

LiH < NaH < KH < RbH < CsH

In ionic hydride as it is formed by the s-Block element, down the group, electropositive character increases.

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option (iv)

Loss of an electron from a hydrogen atom results in a nucleus of very small size as compared to other atoms or ions. Due to its small size it cannot exist free.

Loss of the electron from hydrogen atom results in nucleus size (H⁺) of 1.5 * 10^-3. This is extremely small as compared to normal atomic and ionic sizes of 50 to 200 pm. As a consequence, H⁺ does not exist freely and is always associated with other atoms or molecules.

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option (ii)

Its tendency to gain a single electron in its valence shell to attain stable electronic configuration.

Like halogens (with ns²np⁵ configuration belonging to the seventeenth group of the periodic table), it is short by one electron to the corresponding noble gas configuration, helium (ls²).