Negative ions are usually formed from: metals nonmetals
2 answers:
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Explanation:
According to law of conservation of mass, mass of the reactants is equal to the mass of products in a chemical equation. As mass can neither be created nor it can be destroyed but it can be transformed from one form to another.
As it is given that hydrogen and in excess oxygen is reacting that leads to the formation of water. Hence, the chemical reaction equation will be as follows.
Since, it is given that 4 mol of hydrogen is reacting with excess of oxygen and gives 2 moles of water.
Hence, number of moles of water produced is calculated as follows.
4 mol of
= 4 moles of
Thus, we can conclude that 4 moles of water you can produce from 4.0 mol of hydrogen and excess oxygen.
Answer : The oxidation-reduction reactions are:
I. reaction of a metal with a nonmetal
II. synthesis
III. combustion
Explanation :
Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.
Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.
Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.
I. Reaction of a metal with a nonmetal :
When sodium react with chlorine gas then it react to give sodium chloride.
In this reaction, the oxidation state of sodium changes from (0) to (+1) and shows oxidation and the oxidation state of chlorine changes from (0) to (-1) and shows reduction. So, It is an oxidation-reduction reaction.
II. Synthesis reaction :
A chemical reaction where multiple substances or reactants combine to form a single product.
When hydrogen react with oxygen then it react to give water.
In this reaction, the oxidation state of hydrogen changes from (0) to (+1) and shows oxidation and the oxidation state of oxygen changes from (0) to (-2) and shows reduction. So, It is an oxidation-reduction reaction.
III. Combustion reaction :
A chemical reaction in which a hydrocarbon reaction with the oxygen to give product as carbon dioxide and water.
When methane react with oxygen gas then it react to give carbon dioxide and water.
In this reaction, the carbon of methane gain oxygen and shows oxidation and the oxygen gas gain hydrogen and shows reduction. So, It is an oxidation-reduction reaction.
IV. Precipitation reaction :
It is defined as the reaction in which an insoluble salt formed when two aqueous solutions are combined.
The insoluble salt that settle down in the solution is known an precipitate.
It is a double displacement reaction. So, it is not an oxidation-reduction reaction.
V. Decomposition reaction :
A chemical reaction in which the the larger molecule decomposes to give two or more smaller molecules.
The oxidation state remains same on reactant and product side. So, it is not an oxidation-reduction reaction.