Embibe Experts Solutions for Chapter: Hydrogen, Exercise 3: Exercise-3

In which of the following reactions, ${\mathrm{H}}_2{\mathrm{O}}_2$ acts as a reducing agent?
 (a) ${\mathrm{H}}_2{\mathrm{O}}_2+2{\mathrm{H}}^{+}+2{\mathrm{e}}^{-}\to 2{\mathrm{H}}_2$
(b) ${\mathrm{H}}_2{\mathrm{O}}_2-2{\mathrm{e}}^{-}\to {\mathrm{O}}_2+2{\mathrm{H}}^{+}$
(c) ${\mathrm{H}}_2{\mathrm{O}}_2+2{\mathrm{e}}^{-}\to 2{\mathrm{OH}}^{-}$
(d) ${\mathrm{H}}_2{\mathrm{O}}_2+2{\mathrm{OH}}^{-} + 2{\mathrm{e}}^{-}\to {\mathrm{O}}_2+2{\mathrm{H}}_2\mathrm{O}$

The reagent commonly used to determine hardness of water titrimetrically is:

When zeolite, which is hydrated sodium aluminium silicate, is treated with hard water, the sodium ions are exchanged with

Polyphosphates are used as water softening agents because they 

A white solid is either Na₂O or Na₂O₂. A piece of red litmus paper turns white when it is dipped into a freshly made aqueous solution of the white solid.
(i) Identify the substance and explain with balanced equation.
(ii) Explain what would happen to the red litmus if the white solid were the other compound.

Hydorgen peroxide acts both as an oxidising and as a reducing agent depending upon the nature of the reacting species. In which of the following cases ${\mathrm{H}}_2{\mathrm{O}}_2$ acts as a reducing agent in acid medium?

The hardness of water sample (in terms of equivalents of ${\mathrm{CaCO}}_3$) containing ${{10}^{-}}^3 \mathrm{M} {\mathrm{CaSO}}_4$ is _____. (Molar mass of ${\mathrm{CaSO}}_4=136 \mathrm{g} {\mathrm{mol}}^{-1}$)

The chemical nature of hydrogen peroxide is :