KPK 9th Class Chemistry Chapter 7 Electrochemistry Short Questions Answers
KPK 9th Class Chemistry Chapter 7 Electrochemistry Short Questions with answers are combined for all 9th class(Matric/ssc) Level students.Here You can prepare all Chemistry Chapter 7 Electrochemistry short question in unique way and also attempt quiz related to this chapter.Just Click on Short Question and below Answer automatically shown. After each question you can give like/dislike to tell other students how its useful for each.
Class/Subject: 9th Class Chemistry
Chapter Name: Electrochemistry
Board: All KPK Boards
- Malakand Board 9th Class Chemistry Chapter 7 Electrochemistry short questions Answer
- Mardan Board 9th Class Chemistry Chapter 7 Electrochemistry short questions Answer
- Peshawar Board 9th Class Chemistry Chapter 7 Electrochemistry short questions Answer
- Swat Board 9th Class Chemistry Chapter 7 Electrochemistry short questions Answer
- Dera Ismail Khan Board 9th Class Chemistry Chapter 7 Electrochemistry short questions Answer
- Kohat Board 9th Class Chemistry Chapter 7 Electrochemistry short questions Answer
- Abbottabad Board 9th Class Chemistry Chapter 7 Electrochemistry short questions Answer
- Bannu Board 9th Class Chemistry Chapter 7 Electrochemistry short questions Answer
Helpful For:
- All KPK Boards 9th Class Chemistry Annual Examination
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KPK 9th Class Chemistry Chapter 7 Electrochemistry Short Questions Answers
In given equation a, Br2 is going to reduce. Its oxidation state changes from 0 to -1
Ca0+ Br20→ Ca+2Br2-1
In given equation b., is Mn going to reduce. Its oxidation state changes from +7 to +2
Mn+7 →Mn+2
Silver at reactant side is present in form of element, so has zero oxidation state. Product side, in form of compound (Ag2O), it has +1 oxidation state.e.g
Oxidation State of Ag = 0, & oxidation State of Ag2O=+1
NaOH is strong but NH4OH is weak electrolyte. It is because NaOH is ionic in nature and hence dissociates completely in water, thus strong electrolyte. One the other hand, NH4OH is partially polar so to little extent it undergoes dissociation, thus weak electrolyte.
It is a slow & continuous process of eating away of a metal due to their chemical contact with environment and atmosphere.
It is a spontaneous process and redox reaction. It take start when metallic surface is exposed to air in presence of moistures.
Method of Prevention of Corrosion
Following methods are used for prevention of corrosion.
- Removal of Stain: The region of stain in an iron act as the site for corrosion. When the surface of iron is properly cleaned and saints are removed, it prevents the process of rusting.
- Barriers –a barrier like paint, for example, will provide a protective coat, thus preventing water or oxygen from coming into contact with the metal.
- Sacrificial coating- another of metal is sacrificed in order to protect the main metal. There are actually a couple of types of sacrificial coating:
- Anodic protection occurs when a metal less likely to corrode is placed on top of a more corrosive-prone metal. For example, tin, which does not corrode, is often placed on top of steel to protect the steel from corrosion.
- Cathodic protection occurs when a metal that will corrode is placed on top of another metal and is ‘sacrificed’ so the main metal will not corrode. For example, zinc is often placed on top of steel to prevent the steel from corroding.
Nelson cell process
At cathode At anode
2H2O+ ↔H2+ 2OH– & 2Cl–→Cl2+2e
Na+OH-↔NaOH
Net Reaction: 2NaCl+2H-OH →NaOH+H2+Cl2
Burning of fuel is the most well known & daily life redox reaction. In such reaction fuel is burnt (oxidized) in presence of oxygen and CO2 and H2O are produced.
Petrol + O2→H2O+ CO2
- Hl b. PBr3 c. CaCO3 d. H3PO4 e. AS3O5
| Molecule | Oxidation No | Molecule | Oxidation No |
|
H= +1, l = -1 |
|
H = +1, P = +5,
O = -2 |
|
P=+5, Br = -1 |
|
|
|
Ca = +2,
C=+4, O= – 2 |
|
H= +2, S= +6,
O = -2 |
Rusting of iron is a redox reaction, in which iron is oxidized by oxygen and oxygen is reduced by iron. The reactions involved are listed below.
2 Fe →2Fe+2+ 4e
2H2O + O2+ 4 e– → 4OH–
The Fe+2 further get oxidation by atmospheric O2Fe+3 as:
Fe+2→Fe+3 + e–
Fe+3 + OH–→Fe(OH)3……..Rust.
The some uses of electrolytic are listed below.
- In electrolytic cell non-spontaneous redox reaction is carried on the expense of electrical energy.
- An electrolyte is separated and decomposed into its components.
- Metals are extracted and purified from their ores.
- In order to prevent metals from corrosion, their electroplating is carried is out in electrolytic cell.
