Redox 1

Question 1

what is oxidation

Answer 1

“oxidation” is defined as the addition
of oxygen/electronegative element to
a substance or removal of hydrogen/
electropositive element from a substance.

It also involves the loss of electrons

Question 2

what is reduction

Answer 2

removal
of oxygen/electronegative element from
a substance or addition of hydrogen/
electropositive element to a substance.

also involves the gain of e-s

Question 3

what is reaction between potassium ferocyanide and hydrogen perxode considered to be

Answer 3

2K4 Fe(CN)6 + H2O2 (aq) →2K3Fe(CN)6
+ 2 KOH (aq

The e removal
of electropositive element potassium from
potassium ferrocyanide before it changes to
potassium ferricyanide

Question 4

what is oxidising agent

Answer 4

a substance that supplies oxygen or other electro-ve elemtn or remove hydrogen or any other electro+ve element.
it gets reduced

Question 5

what is reducing agent

Answer 5

a substance that supplies hydrogen or other electro+ve element or remove oxygen or any other electro-ve element.

it gets oxidised

Question 6

zn rod in cuso4 solution

Answer 6

You may notice
that the strip becomes coated with reddish
metallic copper and the blue colour of the
solution disappears. Formation of Zn2+ ions
among the products can easily be judged
when the blue colour of the solution due to
Cu2+ has disappeared. If hydrogen sulphide
gas is passed through the colourless solution
containing Zn2+ ions, appearance of white zinc
sulphide, ZnS can be seen on making the
solution alkaline with ammonia.
The reaction between metallic zinc and the
aqueous solution of copper nitrate is :
Zn(s) + Cu2+ (aq) → Zn2+ (aq) + Cu(s)

Question 7

co in nickel solution

Answer 7

the reaction of metallic cobalt placed in nickel
sulphate solution. At equilibrium, chemical tests reveal that both
Ni2+(aq) and Co2+(aq) are present at moderate
concentrations. In this case, neither the
reactants [Co(s) and Ni2+(aq)] nor the products
[Co2+(aq) and Ni (s)] are greatly favoured.

Question 8

what is competitive elctron transfer

Answer 8

There is a competition for the release of electrons by different metals. The different metals are ranked according to their e- losing capability in the metal reactivity series.

electrochemical series

Question 9

what is oxidation number

Answer 9

Oxidation number denotes the oxidation
state of an element in a compound
ascertained according to a set of rules
formulated on the basis that electron pair in a covalent bond belongs entirely to more
electronegative element.

Question 10

differentiate between valency and oxidation state

Answer 10

Valency
- it is combining capacity of the atom
- valency of an element is just a no without any sign
- except noble gases, no other element has 0 valency
- valency is always a whole no
- in most cpds, an element has a fixed no for valency

oxidn state
- it is the charge assigned to the element based on some fixed rules
- it has +ve or -ve sign
- all elements have 0 oxidn state in free/ uncombined state
- oxidation can even be a fraction
- the oxidn state of an element is different in different cpds. Oxygen

Question 11

what is stock notation

Answer 11

the oxidation
number is expressed by putting a Roman
numeral representing the oxidation number
in parenthesis after the symbol of the metal in
the molecular formula
AuCl SIlver (I) Chloride
AuCl3 Silver (III) Chloride

Question 12

what are redox reactions

Answer 12

Oxidation: An increase in the oxidation
number of the element in the given substance.
Reduction : A decrease in the oxidation
number of the element in the given substance.
Oxidising agent: A reagent which can
increase the oxidation number of an element
in a given substance. These reagents are
called as oxidants also.
Reducing agent: A reagent which lowers the
oxidation number of an element in a given
substance. These reagents are also called as
reductants.
Redox reactions: Reactions which involve
change in oxidation number of the interacting
species