Redox Reactions Test - 1

Explanation:

X=-1.2V , Y=+0.5V , Z=-3.0V Therefore, Z>X>Y

Because, higher the reduction potential ,lesser the reducing power.

Explanation:

A combination reaction (also known as a synthesis reaction) is a reaction where two or more elements or compounds (reactants) combine to form a single compound (product). Such reactions may be represented by equations of the following form: X + Y → XY.

Explanation:

Color in complex arises due to the presence of unpaired electrons in the system when complex reaction takes place.

Explanation:

The roman number represents the oxidation number/oxidation state of an element.It is popularly known as Stock notation given by the german scientist Alfred stock.

Explanation:

Oxygen is the most electronegative element. Oxygen have 6 electrons in its outermost shell and to gain noble gas configuration oxygen have to take 2 more electrons.

Explanation:

The highest value of oxidation number exhibited by an atom of an element generally increases across the period in the periodic table.

Explanation:

Oxidation number is a number assigned to an element in a compound according to some rules. This number enable us to describe oxidation-reduction reactions, and balancing redox chemical reactions. When a covalent bond forms between two atoms with different electronegativities the shared electrons in the bond lie closer to the more electronegative atom eg. HCl

The oxidation number of an atom is the charge that results when the electrons in a covalent bond are assigned to the more electronegative atom. It is the charge on an atom would possess if the bonding were ionic. In HCl (above) the oxidation number for the hydrogen would be +1 and that of the Cl would be -1

Explanation:

Zinc relases electrons to copper and copper releases electron to silver therefore the electron releasing tendency of the metals, zinc, copper and silver is in the order Zn>Cu>Ag.This is on the basis of electrochemical series or metal activity series.

Explanation:

Oxidation means addition of oxygen, removal of hydrogen, increase in oxidation number, addition of a electronegative element or removal of an electropositive element

​​​​​​The term oxidation was first used to describe chemical reactions in which oxygen was added to an element of a compound. Later on the term oxidation was extended to describe many more reactions which occurred without the use of even oxygen.

Addition of Oxygen: Oxidation is a chemical reaction in which oxygen is added to any chemical species (atom, ion or molecule). Example

2Mg + O2 → 2MgO

S + O2 → SO2

2CO + O2 → 2CO2

Na2SO3 + H2O2 → Na2SO4 + H2O

Removal of Hydrogen : Oxidation is a chemical reaction in which hydrogen is removed from any chemical species (atom, ion or molecule).

H2S + Cl2 → 2HCl + S

4HI + O2 → 2H2O + 2I2

4HI + MnO2 → MnCl2 + 2H2O + Cl2

Addition of an Electronegative Element: Oxidation is a chemical reaction in which an electronegative element is added into any chemical species (atom, ion or molecule).

Fe+ S → FeS (Oxidation of iron)

SnCl2 + Cl2→ SnCl4(Oxidation of stannous chloride)

2Fe + 3F2 → 2FeF3(Oxidation of iron)

Removal of an Electropositive Element: Oxidation is a chemical reaction in which an electropositive element is removed from any chemical species (atom, ion or molecule).

2KI + H2O2 → 2KOH + I2 (Oxidation of potassium iodide)

2K2MnO4 + Cl2 → 2KCl + 2KMnO4 (Oxidation of potassium manganate)

2KI + Cl2 → 2KCl + I2 (Oxidation of potassium iodide)

A substance which brings oxidation is known as oxidizing agentt

Explanation:

Reduction is addition of hydrogen, removal of oxygen, removal of an electronegative element or addition of an electropositive element.

Removal of Oxygen: Reduction is a chemical reaction in which oxygen is removed from any chemical species (atom, ion or molecule).

CuO + C → Cu + CO

H2O + C → CO + H2

2CO + O2 → 2CO2

Fe3O4 + 4H2 → 3F2 + 4H2O

Addition of Hydrogen : Reduction is a chemical reaction in which hydrogen is added to any chemical species (atom, ion or molecule).

Cl2 + H2 → 2HCl

S + H2 → H2S

C2H4 + H2 → C2H6

Removal of an Electronegative Element: Reduction is a chemical reaction in which an electronegative element is removed from any chemical species (atom, ion or molecule).

2HgCl2 + SnCl2 → Hg2Cl2 + SnCl4 (Reduction of mercuric chloride)

2FeCl3 + H2 → 2FeCl2 + 2HCl (Reduction of ferric chloride)

2FeCl3 + H2S → 2FeCl2 + 2HCl + S (Reduction of ferric chloride)

Addition of an Electropositive Element: Reduction is a chemical reaction in which an electropositive element is added any chemical species (atom, ion or molecule).

HgCl2 + Hg → Hg2Cl2 (Reduction of mercuric chloride)

CuCl2 + Cu → Cu2Cl2 (Reduction of cupric chloride)

The substance which brings reduction is known as reducing agent.

A substance, which undergoes oxidation, acts as a reducing agent while a substance, which undergoes reduction, acts as an oxidizing agent.

Mg, S, Cu, Na2SO3, H2S, HI, H2, C, KI are reducing agents, while O2, Cl2, F2, H2O2, MnO2, FeCl3, CuCl2, Fe3O4, CuO, etc., are oxidizing agents in the above examples.

All oxidation and reduction reactions are complimentary of one another and occur simultaneously, one cannot take place without the other.

No single oxidation and no single reduction process is known. The simultaneously oxidation and reduction reactions are generally termed as redox reactions. e.g., 2FeCl3 + SnCl2 → 2FeCl2 + SnCl4.

In above example iron undergoes reduction from +3 to +2.