Question

please answer the question correctly

Answer 1

A) Oxidation refers to losing of electrons while reduction refers to the gaining of electrons. The reactions in which oxidation and reduction takes place simultaneously are referred to redox reaction. For e.g.

CuO + H2 → Cu + H2O
Here copper oxide is reduced and thus acts as oxidizing agent.H2 is oxidized and acts as reducing agent.

There are reactions in which oxidation and reduction of same compound results. Such reactions are called disproportionation reaction. For e.g. on heating potassium chlorate we get

2KClO3 → 2KCl + 3O2

The other example is

2H2O2 → 2H2O + O2




C) A substance participating in a chemical reaction, present at the beginning of a chemical reaction or molecules before it undergoes a chemical change is called a reactant.

A chemical substance formed as a result of a chemical reaction is called a product.

A chemical reaction is a process that leads to the transformation of one set of chemical substances to other new substances.

The chemical reaction H2(g) + ½ O2(g) → H2O(l) describes the formation of water from its elements.

H2(g) + ½ O2(g) → H2O(l)

Reactants Product..




D) Combination Reactions:-------
• Is also referred to as a synthesis reaction
• It is a chemical change in which two or more substances react to form a new singular substance
• The product is a compound in this form of reaction
• You can tell this reaction has occurred because on the reactant side there are multiple substances, while on the product side there is only one product

eg:-2 H2 + O2----->2H20

​2) Decomposition: A decomposition reaction is the opposite of a synthesis reaction - a complex molecule breaks down to make simpler ones. These reactions come in the general form:
AB ---> A + B
This type of reaction is easily identifiable, because: • It is the exact opposite of synthesis; if you know one you know them both
• There is always one reactant. If you see one reactant that’s a compound and several products, a decomposition reaction occurred.
One example of a decomposition reaction is the electrolysis of water to make oxygen and hydrogen gas:
2 H2O ---> 2 H2 + O2

3) Single displacement: This is when one element trades places with another element in a compound. These reactions come in the general form of:
A + BC ---> AC + B
It is identifiable by its symmetry. On the reactant side there is a single element and a compound, as there is on the product side.
• No reaction will occur if the most reactive element is already in the compound
One example of a single displacement reaction is when magnesium replaces hydrogen in water to make magnesium hydroxide and hydrogen gas:
Mg + 2 H2O ---> Mg(OH)2 + H2

4) Double displacement: This is when the anions and cations of two different molecules switch places, forming two entirely different compounds. These reactions are in the general form:
AB + CD ---> AD + CB
Generally take place in aqueous solution
• Often produce a precipitate, a gas, or a molecular compound (i.e. water)
One example of a double displacement reaction is the reaction of lead (II) nitrate with potassium iodide to form lead (II) iodide and potassium nitrate:
Pb(NO3)2 + 2 KI ---> PbI2 + 2 KNO3

5)Oxidation → When a substance gains oxygen or looses hydrogen.
Oxidation in everyday life. eg:-Cu + O2--->2CuO
Corrosion – When a metal is oxidised by action of air and moisture [that’s why metals are coated]
Rancidity – When fats and oils are oxidised, their smell and taste change [that’s why food is kept in air-tight containers]
Reduction → When one substance loses oxygen or gains hydrogen​
EG:-- CuO + H2---->Cu+ H2O