How many moles of potassium dichromate (K₂Cr₂O₇) are required to reduce 1 mole of  Sn ²⁺ in an acidic medium? 

1.  1/3

2. 1/6

3. 2/3

4. 1

${\mathrm{MnO}}_4^{2-}$ (1 mole ) in neutral aqueous medium will disproportionate to :

1. 2/3 Mole of ${\mathrm{MnO}}_4^{-}$ and 1/3 mole of ${\mathrm{MnO}}_2$

2. 1/3 Mole of ${\mathrm{MnO}}_4^{-}$ and 2/3 mole of ${\mathrm{MnO}}_2$

3. 1/3 Mole of ${\mathrm{Mn}}_2{\mathrm{O}}_7$ and 1/3 mole of ${\mathrm{MnO}}_2$

4. 2/3 Mole of ${\mathrm{Mn}}_2{\mathrm{O}}_7$ and 1/3 mole of ${\mathrm{MnO}}_2$

The oxidation number of oxygen in ${\mathrm{KO}}_3$ $\mathrm{and}$ ${\mathrm{Na}}_2{\mathrm{O}}_2$ is respectively -

1. 3, and 2
2. 1, and 0
3. 0, and 1
4. -0.33, and -1

The oxidation number of phosphorus in \(Ba \left(H_{2} PO_{2}\right)_{2}\) is-

1. -1

2. +1

3. +2

4. +3

2 mole of ${\mathrm{N}}_2{\mathrm{H}}_4$ loses 16 mole of electron is being converted to a new compound X. Assuming that all of the N appears in the new compound. What is the oxidation state of 'N' in X ?

1. -1

2. -2

3. +2

4. +4

Given the following reaction: 

\(K_2Cr_2O_7 \ \rightarrow K_2CrO_4\)

The change in the oxidation state of chromium in the above conversion is:
1. 0
2. 6
3. 4
4. 3

When a manganous salt is fused with a mixture of ${\mathrm{KNO}}_3$ and solid NaOH, the oxidation number of Mn changes from +2 to :

1. +4

2. +3

3. +6

4. +7

In $\mathrm{Fe}\left(\mathrm{II}\right)-{\mathrm{MnO}}_4^{-}$ titration, ${\mathrm{HNO}}_3$, is not used because :

1. it oxidises ${\mathrm{Mn}}^{2+}$

2. it reduces ${\mathrm{MnO}}_4^{-}$

3. it oxidises ${\mathrm{Fe}}^{2+}$

4. it reduces ${\mathrm{Fe}}^{3+}$ formed

Which species are oxidized and reduced in the given reaction?

${\mathrm{FeC}}_2{\mathrm{O}}_4+{\mathrm{KMnO}}_4\to {\mathrm{Fe}}^{3+}+{\mathrm{CO}}_2+{\mathrm{Mn}}^{2+}$

1. Oxidised : Fe,C ; Reduced : Mn

2. Oxidised : Fe; Reduced : Mn

3. Reduced : Fe,Mn ; Oxidised : C

4. Reduced : C; Oxidised : Mn,Fe

Reaction that shows ${\mathrm{H}}_2{\mathrm{O}}_2$ as a reducing agent is -

1. ${\mathrm{SO}}_2+{\mathrm{H}}_2{\mathrm{O}}_2\to {\mathrm{H}}_2{\mathrm{SO}}_4$

2. $2\mathrm{KI}+{\mathrm{H}}_2{\mathrm{O}}_2\to 2\mathrm{KOH}+{\mathrm{I}}_2$

3. $\mathrm{PbS}+4{\mathrm{H}}_2{\mathrm{O}}_2\to {\mathrm{PbSO}}_4+4{\mathrm{H}}_2\mathrm{O}$

4. ${\mathrm{Ag}}_2\mathrm{O}+{\mathrm{H}}_2{\mathrm{O}}_2\to 2\mathrm{Ag}+{\mathrm{H}}_2\mathrm{O}+{\mathrm{O}}_2$