Which of the following is the strongest reducing agent?

[Given: \(E_{Cl_{2}/Cl^{-}}^{o} = 1.36 V\); \(E_{Cr^{3+}/Cr}^{o} = -0.74 V\); 
\(E_{Cr_20_7^{2-}/Cr^{3+}}^{o} = 1.33 V\) and \(E_{MnO_4^{-}/Mn^{2+}}^{o} = 1.51 V\)]

1.	Cr3+	2.	Cl–
3.	Cr	4.	Mn2+

Which of the following reactions is an example of a redox reaction?

1.  \(XeF_6+H_2O~\longrightarrow~XeOF_4+2HF\)
2.  \(XeF_6+2H_2O~\longrightarrow~XeO_2F_2+4HF\)
3.  \(XeF_4+O_2F_2~\longrightarrow~XeF_6+O_2\)
4.  \(XeF_2+PF_5~\longrightarrow~[XeF]^{+1}+PF_6~^-\)

Consider the following reaction :
\(a\mathrm{Cu}+b\mathrm{HNO}_{3} \rightarrow c\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}+d\mathrm{NO}+e\mathrm{H}_{2} \mathrm{O}\)
The values of a, b, and e in the reaction are, respectively:
1. 3, 8 and 4
2. 5, 2 and 8
3. 5, 2 and 16
4. 2, 5 and 8

Given 
\(\mathrm{E}_{\mathrm{Cr}^{3+} / \mathrm{Cr}}^0=-0.74 \mathrm{~V} ; \mathrm{E}_{\mathrm{MnO}_4^{-} / \mathrm{Mn}^{2+}}^0=1.51 \mathrm{V}\\{E}_{\mathrm{Cr}_2 \mathrm{O}_7^{2-} / \mathrm{Cr}^{3+}}^0=1.33 \mathrm{~V} ; \mathrm{E}_{\mathrm{Cl}_2 / \mathrm{Cl}^{-}}^0=1.36 \mathrm{~V}\)

Based on the data given above, strongest oxidizing agent will be:

Find the metal used for coating iron during the process of galvanization.

Amount of oxalic acid present in a solution can be determined by its titration with KMnO₄ solution in the presence of H₂SO₄.
The titration gives unsatisfactory result when carried out in the presence of HCl, because HCl does which of the following?

1. It furnishes H⁺ ions in addition to those from oxalic acid

2. It reduces permanganate to Mn²⁺

3. It oxidises oxalic acid to carbon dioxide and water

4. It gets oxidised by oxalic acid to chlorine

The reaction of sulphur in an alkaline medium is given below:

${\mathrm{S}}_{8\left(\text{\hspace{0.17em}s}\right)}+{{\mathrm{aOH}}^{-}}_{\left(\mathrm{aq}\right)}\to {{\mathrm{bS}}^{2-}}_{(\mathrm{aq})}+{\mathrm{cS}}_2{{\mathrm{O}}_3^{2-}}_{\text{(aq)\hspace{0.17em}}}+{\mathrm{dH}}_2{\mathrm{O}}_{\left(\mathrm{\ell }\right)}$

The value of 'a' is: 

A 20.0 mL solution containing 0.2 g impure H₂O₂ reacts completely with 0.316 g of KMnO₄ in acid solution. What is the percentage purity of H₂O₂ ?
[Given: mol. wt. of H₂O₂ = 34 ; mol. wt. of KMnO₄ = 158]

1. 80
2. 85
3. 90
4. 92

The oxidation states of transition metal atoms in K₂Cr₂O₇, KMnO₄ and K₂FeO₄, respectively, are x, y and z.
The sum of x, y and z is:

1. 16

2. 12

3. 19

4. 22

The oxidation states of iron atoms in compounds (A), (B) and (C), respectively, are x, y and z. The sum of x, y and z is________.

Na₄[Fe(CN)₅NOS]         Na₄[FeO₄]       [Fe₂(CO)₉]

           (A)                         (B)                   (C)

1. 4  

2. 5

3. 6

4. 7