Question

what are features of chemical reaction explain with example .
plz ans to be brainlist it is request plz ans fast.

Answer 1

*Acid and Bases
Many substances are known as acids and bases In the HandbookMenu, some properties of acids and bases are given in two tables and you may click them to find out their names and formulas. Reactions between acids and bases are called acid-base reactions. Some of them are often called neutralization reactions.However, the concepts of acids and bases have been generalized and much more discussion can be found in modules or units in Chem123/125. Thus, acid-base reactions are further subdivided into other types. A few examples are given below,HCl + NaOH = NaCl + H2 . . . neutralization
HCl + NH3 = NH4Cl . . . formation of a salt from vapour
CH3COOH + H2O = CH3COO- + H3O+ . . . ionization
CH3COOH + NaHCO3 = NaCH3COO + CO2 . . . gas formation
*Combination
A combination reaction refers to one in which two or more substances react (or combine) to give one new product. Elements combine to form compound, but compounds may also do the same. The following are combination reactions:H2(g) + Cl2(g) = 2 HCl(g)
Fe(s) + S(s) = FeS(s)
NH3(g) + HCl(g) = NH4Cl(s, appear as a white smoke)
2 Na(s) + Cl2(g) = 2 NaCl(s)
2 NO(g) + O2(g) = 2 NO2(g)
P4O10(s) + 6 H2O(l) = 4 H3PO4(aq)
*Combustion
A substance reacts with oxygen or oxygen in the air to give oxides in a combustion reaction. For example the combustion of alcohol, sulfur and magnesium are given below:C2H5OH(l) + O2(g) = CO2(g) + H2O(g)
S(s) + O2(g) = SO2(g)
2 Mg(s) + O2(g) = 2 MgO(s)
It's interesting to point out that at very high temperature, a combustion reaction favors the formation of CO rather than CO2, especially when oxygen supply is limited. The combustion of CO with oxygen release energy, and at high temperature, abundance of energy in the system keeps CO from further oxidation.*Decomposition
A compound or substance separate into two or more substances which may or may not be different from each other, but the products are usually different from the original compound. Some examples of decomposition reactions are:2 H2O(l) = 2 H2 + O2 . . . electrolysis of water
2 HgO(s) = 2 Hg(l) + O2(g) . . . generation of oxygen from heating HgO
2 KClO3(s) = 2 KCl(s) + 3 O2(g) . . . another way to produce oxygen
CH3COOH = CH4 + CO2Note however, the following reactions are often called ionization or dissociation reactions rather than decomposition reaction. The solvent participates in these reactions.NaCl(s) + 6 H2O = Na+(H2O)6 + Cl-
NH4Cl(s) = NH4+(aq) + Cl-
HNO2 = H+(aq) + NO2-(aq)Some decomposition reactions are Disproportion Reactions. For example,3 Cl2(g) + 6 OH-(aq) = 5 Cl- + ClO3-(aq) + 3 H2O(l)
4 KClO3(s) = KCl(s) + 3 KClO4(s)
*Displacement
Due to difference in affinity, part of a compound may be replaced by another element or a group of atoms. The following reactions illustrate not only the displacement reactions, but also the relative reactivity of some elements:Zn + H2SO4 = ZnSO4 + 2 H2 . . . Zn displaces hydrogen
2 HCl + F2 = 2 HF + Cl2 . . . F displaces Cl
2 Na + H2O = 2 NaOH + H2 . . . Na displaces H
2 Al + Fe2O3 = 2 Fe + Al2O3 . . . a thermite reaction*Oxidation and Reduction
Oxidation and reduction reactions usually involve the transfer of electrons. A gain of electron is called reduction, and a loss of electron is oxidation. Since electrons can neither be created nor destroyed a gain of electrons by one species must be accompanied by a loss of another species. Thus, oxidation reactions are always accompanied by reductions, and reactions of this type are called redox reactions. These reactions are the basis forbattery or Daniel cell operations.Before the realization of electron transfers, reactions with oxygen were called oxidation reaction, and reactions with hydrogen or with base-forming elements such as metals were called reduction reactions. However, the more modern definition will be used in our discussion of chemistry.There are many redox reactions, and balancing redox reaction equation is a basic skill for an educated person. A unit will be devoted to balance redox reaction equations in this course. This type of reactions may belong to types mentioned earlier. Please identify the species that are oxidized and reduced in the following reactions,Zn + H2SO4 = ZnSO4 + 2 H2; (zinc oxidized)
2 HCl + F2 = 2 HF + Cl2 (flourine reduced)
2 Na + H2O = 2 NaOH + H2 (hydrogen reduced)
2 Al + Fe2O3 = 2 Fe + Al2O3
2 HgO = 2 Hg + O2 (oxygen oxidized)
2 KClO3 = 2 KCl + 3 O2 (chlorine reduced)
C2H5OH + O2 = CO2 + H2O
*Precipitation
Solids appear when two solutions are mixed if the products formed are not soluble. The solids are called precipitates, and such reactions are called precipitation reactions. In reaction equations, we use (s) to represent the formation of a solid or precipitate (ppt).AgNO3 + NaCl = NaNO3 + AgCl(s)
PbNO3 + KI = PbNO3 + PbI(s)



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Answer 2

it a reaction in which one or more compound combine to form new compounds
ex.. c+1/2o2=c02