Redox Reactions

The oxidation states of sulphur in the anions SO${}_3^{2-}$ , S₂O_{${}_4^{2-}$} and S₂O${}_6^{2-}$ follow the order

• ${\mathrm{S}}_2{\mathrm{O}}_4^{2-} < {\mathrm{SO}}_3^{2-} < {\mathrm{S}}_2{\mathrm{O}}_6^{2-}$

• ${\mathrm{SO}}_3^{2-} <{\mathrm{S}}_2{\mathrm{O}}_4^{2-} < {\mathrm{S}}_2{\mathrm{O}}_6^{2-}$

• ${\mathrm{S}}_2{\mathrm{O}}_4^{2-} < {\mathrm{S}}_2{\mathrm{O}}_6^{2-} < {\mathrm{SO}}_3^{2-}$

• ${\mathrm{S}}_2{\mathrm{O}}_6^{2-} < {\mathrm{S}}_2{\mathrm{O}}_4^{2-} <{\mathrm{SO}}_3^{2-}$

Very dilute nitric acid reacts with zinc to form zinc nitrate and

• ammonium nitrate

• NO₂

• NO

• N₂O

Volume of CO₃ obtained by the complete decomposition of 9.85 g BaCO₃ is

• 2.24 L

• 1.12 L

• 0.84 L

• 0.56 L

The reduction potential of three metallic ions X, Y and Z correspondingly are +0.52,-303 and -1.18 V. The sequence of reducing capacity of these metals will be

• Y >Z >X

• X >Y >Z

• X >Z >Y

• Z >X >Y

For the reaction ${\mathrm{MnO}}_4^{-} + {\mathrm{C}}_2{\mathrm{O}}_4^{2-} + {\mathrm{H}}^{+} \to {\mathrm{Mn}}^{2+} + {\mathrm{CO}}_2 + {\mathrm{H}}_2\mathrm{O}$.  Which of the following is correct?

• Mn2+	${\mathrm{C}}_2{\mathrm{O}}_4^{2-}$	CO2	H+
  5	2	4	10

• Mn+	${\mathrm{C}}_2{\mathrm{O}}_4^{2-}$	CO2	H+
  2	5	10	16

• Mn2+	C2O${}_4^{2-}$	CO2	H+
  6	8	16	18

• Mn2+	C2O${}_4^{2-}$	CO2	H+
  10	12	24	12

Acidic K₂Cr₂O₇ reacting with H₂S₂ the oxidation number of chromium is changed

• from +3 to +6

• from+6 to +3

• from +6 to +2

• remains unchanged

Which of the following is reducing agent?

• LiAlH₄

• Zn + HCl

• Sn + HCl

• All of the above

The process of oxidation involve

• loss of electron

• gain of electron

• loss of proton

• loss of neutron

The number of electrons transferred when KMnO₄ acts as an oxidising agent to give MnO₂ and Mn²⁺ respectively are

• 2, 3

• 1, 5

• 3, 5

• 1, 3

The reaction,

3ClO^- (aq) → ClO${}_3^{-}$ (aq) + 2Cl^- (aq) is an example of

• oxidation reaction

• reduction reaction

• disproportionation reaction

• decomposition reaction