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CHXI08:REDOX REACTIONS

315067 If \({{\text{H}}_{\text{2}}}{\text{S}}\) gas is passed through acidified solution of \(\mathrm{\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}}\), the colour of the solution will

1 remain unchanged

2 become deep red

3 become green

4 become deep gray

CHXI08:REDOX REACTIONS

315068 A bottle of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) is labelled as 10 vol \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2} . 112 \mathrm{~mL}}}\) of this solution of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) is titrated against 0.04 M acidified solution of \({\mathrm{\mathrm{KMnO}_{4}}}\). The volume of \({\mathrm{\mathrm{KMnO}_{4}}}\) in litre is

1 1

2 2

3 5

4 10

CHXI08:REDOX REACTIONS

315069 100 mL of ozone at STP were passed through 100 mL of 10 volume \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) solution. What is the volume strength of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) after the reaction?

1 5.6

2 11.2

3 9.5

4 2.8

Explanation:

\[\begin{array}{l}
\quad \quad {{\rm{O}}_3} \to \,\,\,\,\,\,\,{{\rm{O}}_2} +\,\,\,\, {\rm{O}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{(1)}}\\
\quad \quad {{\rm{H}}_2}{{\rm{O}}_2} \to {{\rm{H}}_2}{\rm{O}} + {\rm{O}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(2)\\
\,\,{\rm{O}}\,\,\,\,\,\,\,\,\,\,\,\, + \,\,\,\,\,\,\,\,{\rm{O}}\,\,\, \to \,\,\,\,{{\rm{O}}_2}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(3)\\
1/2{\rm{vol}}\,\,\,\quad 1/2\,\,\,{\rm{vol}}\quad \,\,\,1{\rm{vol}}
\end{array}\]
From Eqs. (1) and (2),
we infer that \({\mathrm{100 \mathrm{~mL}_{\mathrm{m}}}}\) of \({\mathrm{\mathrm{O}_{3}}}\) at STP will produce 100 mL of molecular \({\mathrm{\mathrm{O}_{2}}}\) as such and 100 mL of oxygen molecule after reaction with \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\).
This new volume of 100 mL of molecular oxygen after reaction with \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) is contributed equally by \({\mathrm{\mathrm{O}_{3}}}\) and \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\). Thus, 50 mL of oxygen have been contributed by \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\).
Again, we know
Volume of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2} \times}}\) Volume strength of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\)
\(=\text { Volume of } \mathrm{O}_{2} \text { at STP }\)
\({\mathrm{\therefore 100 \mathrm{~mL}}}\) of \({\rm{'10}}\;{\rm{V}}\,{\rm{'}}{{\rm{H}}_{\rm{2}}}{{\rm{O}}_{\rm{2}}} \equiv {\rm{1000}}\;{\rm{mL}}\) of \({\mathrm{\mathrm{O}_{2}}}\) at STP After utilisation of 50 mL of \({\mathrm{\mathrm{O}_{2}}}\), according to Eq. (iii), the balance \({\mathrm{(1000-50)=950 \mathrm{~mL}}}\) of \({\mathrm{\mathrm{O}_{2}}}\) at STP are still retainable by 100 mL of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\).
Hence volume strength of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) after reaction\(=\dfrac{\text { Volume of } \mathrm{O}_{2} \text { at STP }}{\text { Volume of } \mathrm{H}_{2} \mathrm{O}_{2}}=\dfrac{950}{100}=9.5 \mathrm{~V}\)
\({\mathrm{\therefore}}\) Volume strength \({\mathrm{=9.5}}\)

CHXI08:REDOX REACTIONS

315067 If \({{\text{H}}_{\text{2}}}{\text{S}}\) gas is passed through acidified solution of \(\mathrm{\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}}\), the colour of the solution will

1 remain unchanged

2 become deep red

3 become green

4 become deep gray

CHXI08:REDOX REACTIONS

315068 A bottle of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) is labelled as 10 vol \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2} . 112 \mathrm{~mL}}}\) of this solution of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) is titrated against 0.04 M acidified solution of \({\mathrm{\mathrm{KMnO}_{4}}}\). The volume of \({\mathrm{\mathrm{KMnO}_{4}}}\) in litre is

1 1

2 2

3 5

4 10

CHXI08:REDOX REACTIONS

315069 100 mL of ozone at STP were passed through 100 mL of 10 volume \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) solution. What is the volume strength of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) after the reaction?

1 5.6

2 11.2

3 9.5

4 2.8

Explanation:

\[\begin{array}{l}
\quad \quad {{\rm{O}}_3} \to \,\,\,\,\,\,\,{{\rm{O}}_2} +\,\,\,\, {\rm{O}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{(1)}}\\
\quad \quad {{\rm{H}}_2}{{\rm{O}}_2} \to {{\rm{H}}_2}{\rm{O}} + {\rm{O}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(2)\\
\,\,{\rm{O}}\,\,\,\,\,\,\,\,\,\,\,\, + \,\,\,\,\,\,\,\,{\rm{O}}\,\,\, \to \,\,\,\,{{\rm{O}}_2}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(3)\\
1/2{\rm{vol}}\,\,\,\quad 1/2\,\,\,{\rm{vol}}\quad \,\,\,1{\rm{vol}}
\end{array}\]
From Eqs. (1) and (2),
we infer that \({\mathrm{100 \mathrm{~mL}_{\mathrm{m}}}}\) of \({\mathrm{\mathrm{O}_{3}}}\) at STP will produce 100 mL of molecular \({\mathrm{\mathrm{O}_{2}}}\) as such and 100 mL of oxygen molecule after reaction with \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\).
This new volume of 100 mL of molecular oxygen after reaction with \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) is contributed equally by \({\mathrm{\mathrm{O}_{3}}}\) and \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\). Thus, 50 mL of oxygen have been contributed by \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\).
Again, we know
Volume of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2} \times}}\) Volume strength of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\)
\(=\text { Volume of } \mathrm{O}_{2} \text { at STP }\)
\({\mathrm{\therefore 100 \mathrm{~mL}}}\) of \({\rm{'10}}\;{\rm{V}}\,{\rm{'}}{{\rm{H}}_{\rm{2}}}{{\rm{O}}_{\rm{2}}} \equiv {\rm{1000}}\;{\rm{mL}}\) of \({\mathrm{\mathrm{O}_{2}}}\) at STP After utilisation of 50 mL of \({\mathrm{\mathrm{O}_{2}}}\), according to Eq. (iii), the balance \({\mathrm{(1000-50)=950 \mathrm{~mL}}}\) of \({\mathrm{\mathrm{O}_{2}}}\) at STP are still retainable by 100 mL of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\).
Hence volume strength of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) after reaction\(=\dfrac{\text { Volume of } \mathrm{O}_{2} \text { at STP }}{\text { Volume of } \mathrm{H}_{2} \mathrm{O}_{2}}=\dfrac{950}{100}=9.5 \mathrm{~V}\)
\({\mathrm{\therefore}}\) Volume strength \({\mathrm{=9.5}}\)

CHXI08:REDOX REACTIONS

315067 If \({{\text{H}}_{\text{2}}}{\text{S}}\) gas is passed through acidified solution of \(\mathrm{\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}}\), the colour of the solution will

1 remain unchanged

2 become deep red

3 become green

4 become deep gray

CHXI08:REDOX REACTIONS

315068 A bottle of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) is labelled as 10 vol \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2} . 112 \mathrm{~mL}}}\) of this solution of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) is titrated against 0.04 M acidified solution of \({\mathrm{\mathrm{KMnO}_{4}}}\). The volume of \({\mathrm{\mathrm{KMnO}_{4}}}\) in litre is

1 1

2 2

3 5

4 10

CHXI08:REDOX REACTIONS

315069 100 mL of ozone at STP were passed through 100 mL of 10 volume \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) solution. What is the volume strength of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) after the reaction?

1 5.6

2 11.2

3 9.5

4 2.8

Explanation:

\[\begin{array}{l}
\quad \quad {{\rm{O}}_3} \to \,\,\,\,\,\,\,{{\rm{O}}_2} +\,\,\,\, {\rm{O}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{(1)}}\\
\quad \quad {{\rm{H}}_2}{{\rm{O}}_2} \to {{\rm{H}}_2}{\rm{O}} + {\rm{O}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(2)\\
\,\,{\rm{O}}\,\,\,\,\,\,\,\,\,\,\,\, + \,\,\,\,\,\,\,\,{\rm{O}}\,\,\, \to \,\,\,\,{{\rm{O}}_2}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(3)\\
1/2{\rm{vol}}\,\,\,\quad 1/2\,\,\,{\rm{vol}}\quad \,\,\,1{\rm{vol}}
\end{array}\]
From Eqs. (1) and (2),
we infer that \({\mathrm{100 \mathrm{~mL}_{\mathrm{m}}}}\) of \({\mathrm{\mathrm{O}_{3}}}\) at STP will produce 100 mL of molecular \({\mathrm{\mathrm{O}_{2}}}\) as such and 100 mL of oxygen molecule after reaction with \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\).
This new volume of 100 mL of molecular oxygen after reaction with \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) is contributed equally by \({\mathrm{\mathrm{O}_{3}}}\) and \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\). Thus, 50 mL of oxygen have been contributed by \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\).
Again, we know
Volume of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2} \times}}\) Volume strength of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\)
\(=\text { Volume of } \mathrm{O}_{2} \text { at STP }\)
\({\mathrm{\therefore 100 \mathrm{~mL}}}\) of \({\rm{'10}}\;{\rm{V}}\,{\rm{'}}{{\rm{H}}_{\rm{2}}}{{\rm{O}}_{\rm{2}}} \equiv {\rm{1000}}\;{\rm{mL}}\) of \({\mathrm{\mathrm{O}_{2}}}\) at STP After utilisation of 50 mL of \({\mathrm{\mathrm{O}_{2}}}\), according to Eq. (iii), the balance \({\mathrm{(1000-50)=950 \mathrm{~mL}}}\) of \({\mathrm{\mathrm{O}_{2}}}\) at STP are still retainable by 100 mL of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\).
Hence volume strength of \({\mathrm{\mathrm{H}_{2} \mathrm{O}_{2}}}\) after reaction\(=\dfrac{\text { Volume of } \mathrm{O}_{2} \text { at STP }}{\text { Volume of } \mathrm{H}_{2} \mathrm{O}_{2}}=\dfrac{950}{100}=9.5 \mathrm{~V}\)
\({\mathrm{\therefore}}\) Volume strength \({\mathrm{=9.5}}\)