The oxidation state of nitrogen in N₃H is:

1. $+\frac{1}{3}$

2. + 3

3. –1

4. $-\frac{1}{3}$

When KMnO₄ acts as an oxidizing agent and ultimately forms \(\left[\mathrm{MnO}_4\right]^{-2}, \mathrm{MnO}_2, \mathrm{Mn}_2 \mathrm{O}_3, \mathrm{Mn}^{+2}\)${}^{}$
then the number of electrons transferred in each case, respectively, are:

What are the values of a, b, c, and d if the chemical reaction below is assumed to be balanced?

$I{O}_3^{-}+a{I}^{-}+b{H}^{+}\to c{H}_{2}O+d{I}_2$

1. 5, 6, 3, 3 

2. 5, 3, 6, 3

3. 3, 5, 3, 6

4. 5, 6, 5, 5

In a balanced equation
$H_{2}S{O}_4+xHI\to H_{2}S+y{I}_2+z{H}_{2}O$, the values of x, y, z are:

Oxidation numbers of P in ${\mathrm{PO}}_4^{3-}$, of S in ${\mathrm{SO}}_4^{2-}$ and that of Cr in ${\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}$are respectively:
1. +5, +6 and +6
2. +3, +6 and +5
3. +5, +3 and +6
4. -3, +6 and +6

In a redox change, the oxidant K₂Cr₂O₇ is always reduced to:

1. Cr⁵⁺

2. Cr⁴⁺

3. Cr³⁺

4. Cr²⁺

Which metal exhibits more than one oxidation states?

1. Na

2. Mg

3. Al

4. Fe

The reaction during which nitrogen gets oxidised is:

1. ${\mathrm{NH}}_4^{+}$ $\to$N₂

2. ${\mathrm{NO}}_3^{-}<mspace\; width="1em"></mspace>\to$NO

3. NO₂ $\to$${\mathrm{NO}}_2^{-}$

4. ${\mathrm{NO}}_3^{-}$$\to$N${\mathrm{H}}_4^{+}$ 

Which among the following is a redox reaction?

1. NaCl + KNO₃ $\to$NaNO₃ + KCl

2. CaC₂O₄ + 2HCl $\to$CaCl₂ + H₂C₂O₄

3. Mg(OH)₂ + 2NH₄Cl $\to$MgCl₂ + 2NH₄OH

4. Zn + 2AgCN $\to$2Ag + Zn(CN)₂

Conversion of PbSO₄ to PbS is:

1. Reduction of S

2. Oxidation of S

3. Dissociation

4. None of the above