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

The following reaction describes the rusting of iron. 

$4\mathrm{Fe}+3{\mathrm{O}}_2\to 4{\mathrm{Fe}}^{3+}+6{\mathrm{O}}^{2-}$

Which one of the following statements is incorrect?

1. This is an example of a redox reaction

2. Metallic iron is reduced to ${\mathrm{Fe}}^{3+}$

3. ${\mathrm{Fe}}^{3+}$ is an oxidising agent

4. Metallic iron is a reducing agent

Which of the following reactions does not involve disproportionation process?

1. ${\mathrm{Cl}}_2+{\mathrm{OH}}^{-}\to {\mathrm{Cl}}^{-}+{\mathrm{ClO}}_3^{-}+{\mathrm{H}}_2\mathrm{O}$

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

3. $2{\mathrm{Cu}}^{+}\to {\mathrm{Cu}}^{2+}+\mathrm{Cu}$

4. ${\left({\mathrm{NH}}_4\right)}_{2}C{r}_2{O}_7\to {\mathrm{N}}_2+{\mathrm{Cr}}_2{\mathrm{O}}_3+4{\mathrm{H}}_2\mathrm{O}$

Which of the following is a redox reaction?

1. ${\mathrm{H}}_2{\mathrm{SO}}_4$ with NaOH

2. Formation of ${\mathrm{O}}_3$ in the atmosphere

3. Evaporation of ${\mathrm{H}}_2\mathrm{O}$

4. Oxides of nitrogen forming nitrogen & oxygen from lightening

Which of the following is a redox reaction ?

1. $2\mathrm{Na}\left[\mathrm{Ag}{\left(\mathrm{CN}\right)}_2\right]+\mathrm{Zn}\to {\mathrm{Na}}_2\left[\mathrm{Zn}{\left(\mathrm{CN}\right)}_4\right]+2\mathrm{Ag}$

2. ${\mathrm{BaO}}_2+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{BaSO}}_4+{\mathrm{H}}_2{\mathrm{O}}_2$

3. ${\mathrm{N}}_2{\mathrm{O}}_5+{\mathrm{H}}_2\mathrm{O}\to 2{\mathrm{HNO}}_3$

4. ${\mathrm{AgNO}}_3+\mathrm{KI}\to \mathrm{AgI}+{\mathrm{KNO}}_3$