Which of the following reactions is a redox reaction?

• 2AgNO₃ + BaCl₂ → 2AgCl + Ba(NO₃)₂

• BaO₂ + H₂SO₄  → BaSO₄ + H₂O₂

• P₂O₅ + 2H₂O  → H₄P₂O₇

• Cu + 2AgNO₃  → 2Ag + Cu(NO₃)₂

In the reaction 2Fe³⁺(aq) + Sn²⁺(aq) → 2Fe²⁺(aq) + A

A belongs to

• Sn⁴⁺(aq)

• Sn²⁺(aq)

• Sn³⁺(aq)

• Sn⁰

For the redox reaction,

Zn (s) + Cu²⁺ (0.1M) → Zn²⁺ (1M) + Cu (s)

taking place in a cell, E${}_{\mathrm{cell}}^{°}$ is 1.10 V. E_cell for the cell will be $\left(2.303\frac{\mathrm{RT}}{\mathrm{F}} = 0.0591\right)$

• 2.14 V

• 1.80 V

• 0.82 V

• 1.07 V

Which of the following occurs at anode?

• Reduction

• Oxidation

• Both (a) and (b)

• None of these

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

47.

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