Question

Explain the physical and chemical properties of heavy water and hydrogen peroxide.​

Answer 1

Answer:

Physical Properties of heavy water:-

• Heavy water has a colourless appearance at STP.
• At room temperatures, it exists as an odourless liquid.
• Since the density of D2O is approximately 11% greater than that of H2O, an ice cube made of deuterium oxide will sink in normal water.
• Heavy water forms a homogeneous mixture when mixed with normal water.

Chemical Properties of heavy water:-

• The isotopes of hydrogen exhibit different chemical behaviour, owing to the differences in their atomic masses.
• The changes to the solvent properties of water due to the presence of high resolution quantities of deuterium can adversely affect biological systems.
• Normal water dissociates to a further extent when compared to heavy water.
• At a given temperature, the concentration of D+ ions in a D2O sample is generally lower than the concentration of H+ ions in an H2O sample.

Physical Properties Hydrogen Peroxide:-

• In the pure state, hydrogen peroxide is almost colourless (very pale blue) liquid.
• It melts at 272.4 K and has a boiling point of 423 K (extrapolated).
• It is miscible in water in all proportions and forms hydrates.

Chemical Properties Hydrogen Peroxide:

• Oxidation Reactions of H2O2
• Oxidizes black Pbs to white PbSO4. Reaction: Pbs + 4H2O2 → PbSO4 + 4H2O
• Oxidises KI to Iodine. Reaction: 2KI + H2O2 → 2KOH + I2
• Oxidizes nitrites to nitrates. Reaction: NaNO2 + H2O2 → NaNO3 + H2O
• Oxidizes acidified Potassium ferrocyanide. Reaction: 2K4Fe(CN)6 + H2SO4 + H2O2 → 2K3Fe(CN)6 + K2SO4 + 2H2O.
• Oxidizes sulphites to sulphates. Reaction: Na2SO3 + H2O2 → Na2SO4 + H2O
• Oxidizes CrO-24 in an acid medium to chromium Peroxide CrO5. Reaction: CrO-24 + 2H+ + 2H2O2 → CrO5 + 3H2O

Bleaching Reactions:-

It bleaches by oxidation. H2O2 bleaches silk, wool, cotton, hair.

• Reaction: H2O2 → H2O + [O] Nascent oxygen
• Coloured substance + [O] → colourless. Reduction Reactions of Hydrogen Peroxide:-
• It reduces Barium Peroxide to monoxide. Reaction: BaO2 + H2O2 → BaO + H2O + O2
• It reduces ozone to oxygen. Reaction: O3 + H2O2 → H2O + 2O2
• It reduces alkaline potassium ferricyanide. Reaction: 2K3Fe(CN)6 + 2KOH + H2O2 → 2K4Fe(CN)6 + 2H2O + O2