In which reaction: $H_2{O}_2 acts as reducing agent?$

1. $A{g}_{2}O+H_2{O}_2\to 2Ag+H_{2}O+O_2$

2. $2KI+ H_2{O}_2\to 2KOH + I_2$

3. $Pbs+4 H_2{O}_2\to Pbs{O}_4+4H_{2}O$

4.$H_2{O}_2+S{O}_2\to H_{2}S{O}_4$

In the equation, 

$N{O}_2^{-}+H_{2}O\to {\mathrm{NO}}_3^{-}+2H^{+} +n{e}^{-}$, n stands for: 

1. 1

2. 2

3. 3

4. 4

The reaction , 

$3Cl{O}^{-}\left(aq\right)\to Cl{O}_3^{-}\left(aq\right) + 2C{l}^{-}\left(aq\right) is an example of:$

1. oxidation reaction 

2. reduction reaction 

3. disproportionation reaction 

4. decomposition reaction 

The oxidation number of Pt in 

${\left[Pt\left(C_2{H}_4\right)C{l}_3\right]}^{-}$is :

1. +1

2. +2 

3. +3

4. +4

Which acts as a reducing agent only?

1.  $H_{2}S$

2.  $S{O}_2$

3.  $HN{O}_3$

4.  $KMn{O}_4$

The number of peroxide linkages in $K_{3}Cr{O}_8$ is/are 

1. 1

2. 2

3. 3

4. 4

1 mole of ${\mathrm{N}}_2{\mathrm{H}}_4$ loses 10 moles of electrons to form a new compound y. Assuming that all nitrogen appears in the new compound, what is the oxidation state of nitrogen in y?

(There is no change in the oxidation state of hydrogen)

1. +3

2. -3

3. -1

4. +5

In the conversion, ${\mathrm{H}}_2{\mathrm{SO}}_4 \to {\mathrm{H}}_2{\mathrm{S}}_2{\mathrm{O}}_8$ which process occurs?

1.  Oxidation

2.  Reduction

3.  Oxidation as well as a reduction

4.  Neither oxidation nor reduction 

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 :

The oxidation state of Cu in  ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_7$  is -

(Yttrium = +3)