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Question: On what basis is a chemical equation balanced?...

On what basis is a chemical equation balanced?

Explanation

Solution

There are some equations which differ in the number of electrons thus in that case we use the half equation method and in cases where number of atoms differ on left hand and right hand side of the equation we use the multiplying stoichiometric rule. While balancing a chemical equation we have to keep in mind that the number of atoms on each side should be equal. We can multiply the stoichiometric coefficient of each reactant and product and make each type of atom the same.

Complete step-by-step answer: A chemical equation is a reaction between reactants, which in the presence of certain reagents reacts in solvent and forms products. The reaction rate can be altered using a catalyst . In these cases catalyst provides an alternative path so that the reactant can easily change up into products. The role of catalyst does not change the stoichiometry of the equation.
Let’s take an example for understanding the balancing of chemical equations. We have reactions taking place in between aluminum nitrate and sodium phosphate. As the anions are nitrates NO3NO_3^ - and phosphate PO43PO_4^{3 - } thus here the change in stoichiometry will change the number of oxygen and nitrogen same and phosphorus.
As we have to balance this equation let it be number as (1)(1) Al(NO3)3+Na3PO4AlPO4+NaNO3(1)Al{(N{O_3})_3}\, + \,N{a_3}P{O_4}\, \to \,AlP{O_4}\, + \,NaN{O_3} - - - - - (1)
We have (1Al,3Na,1P,3Nand13O)(1Al,\,3Na,\,1P,\,3N\,and\,13O) on the left hand side of reaction and (1Al,1Na,1P,1Nand7O)(1Al,\,1Na,\,1P,\,1N\,and\,7O) on the right hand side of reaction. Let’s try to balance them first by multiplying the left hand side. This is because the left hand side has lesser atoms. We have sodium, nitrogen and oxygen unbalanced while all others are balanced. Now for balancing them we have to multiply sodium nitrate NaNO3NaN{O_3} by 33 because after that the atoms of sodium and nitrogen become equal on both sides.
Now we get the equation after multiplication as, Al(NO3)3+Na3PO4AlPO4+3NaNO3(2)BalancedchemicalequationAl{(N{O_3})_3}\, + \,N{a_3}P{O_4}\, \to \,AlP{O_4}\, + \,3NaN{O_3} - - - - - - - (2)\,Balanced\,chemical\,equation , now we have to count the number of atoms of each type on both side, (1Al,3Na,1P,3Nand13O)(1Al,\,3Na,\,1P,\,3N\,and\,13O) on left and (1Al,3Na,1P,3Nand13O)(1Al,\,3Na,\,1P,\,3N\,and\,13O). The equation is balanced now. As there are an equal number of atoms on both sides we can say that the above equation is balanced now.
We can also balance a number of equations using the multiplying stoichiometry.

Note: There are some equations where the number of atoms is the same sometimes in those cases we can make the proper balancing aware using the number of electrons on both sides. There are cases in which water hydration plays an important role, like the reaction of copper sulphate CuSO4.5H2OCuS{O_4}.5{H_2}O with Iron. In this case we just have to remove the water of crystallization and then balance remaining as above.