Question

Balance the following chemical equations:
(a)- $HN{{O}_{3}}+Ca{{(OH)}_{2}}\to Ca{{(N{{O}_{3}})}_{2}}+{{H}_{2}}O$
(b)- $NaOH+{{H}_{2}}S{{O}_{4}}\to N{{a}_{2}}S{{O}_{4}}+{{H}_{2}}O$
(c)- $NaCl+AgN{{O}_{3}}\to AgCl+NaN{{O}_{3}}$
(d)- $BaC{{l}_{2}}+{{H}_{2}}S{{O}_{4}}\to BaS{{O}_{4}}+HCl$

Answer 1

Balancing a chemical equation involves the addition of stoichiometric coefficients to the reactants and products which will make the atoms of the same element equal in the reactant as well as in the product side. Balancing a chemical equation is important because it obeys the law of conservation of mass and the law of constant proportions.

Complete Step by step answer:
-A chemical equation is a symbolic representation of a chemical reaction in which the reactants react with each other giving product(s). The reactants are written on the left side of the arrow and product(s) are written on the right side of the arrow.
-A positive rational number which describes the total number of molecules of a chemical species that participates in a chemical reaction is known as a stoichiometric coefficient. Stoichiometric coefficient gives the ratio between the reacting species and the products formed in the reaction.
-For balancing a chemical reaction, we need to follow the following steps-
(i) The unbalanced reaction must be obtained from the chemical formulae of the reactants and the products taking part in the chemical reaction.
(ii) Identify the reactants and components from the given equation. The total number of atoms of each element on the reactant side and product side must be balanced. For this compare the number of atoms present in the reactant side with the product side.
(iii) Multiply the total number of atoms present in the reactant and the total number of atoms in the product.
(iv) Stoichiometric coefficients are added to the molecules which have a different number of atoms in the reactant and product side. The coefficient must be added in such a way that it balances the number of atoms on each side. It is important to note here that the number of atoms of an element in one species must be obtained by multiplying the stoichiometric coefficient with the total number of atoms of particular atoms present in one molecule of the species.
(v) The above step is repeated till all the number of atoms in the reactant side are equal to the number of an atom in the product side.
(vi) Once all the individual elements are balanced, now recheck for the number of atoms to be balanced on both sides. If it is so, then the chemical equation is now said to be balanced.
-This method of balancing equation is known as the traditional method of balancing equation.

-Following the above steps, let us now balance the chemical equations given to us-
(A)- $2HN{{O}_{3}}+Ca{{(OH)}_{2}}\to Ca{{(N{{O}_{3}})}_{2}}+2{{H}_{2}}O$
(B)- $2NaOH+{{H}_{2}}S{{O}_{4}}\to N{{a}_{2}}S{{O}_{4}}+2{{H}_{2}}O$
(C)- $NaCl+AgN{{O}_{3}}\to AgCl+NaN{{O}_{3}}$
(D)- $BaC{{l}_{2}}+{{H}_{2}}S{{O}_{4}}\to BaC{{l}_{2}}+2HCl$

Note: Another method for balancing chemical equation is by Algebraic balancing method-
(i) The unbalanced reaction must be obtained from the chemical formulae of the reactants and the products taking part in the chemical reaction.
(ii) Algebraic variables are assigned to each of the reactant and product species as stoichiometric coefficients in the unbalanced equations.
(iii) The set of equations are formulated considering the number of reactants needed to form a particular number of atoms in the product.
(iv) The equations for each element are listed together to form a system of equations. Although this step can have multiple values for the algebraic values, we require only the minimal values of the variables. To obtain this, a value which is a positive integer is assigned to one of the coefficients. If the fractional values are obtained, the lowest common denominator between all the variables is multiplied with each variable because the variables hold the values of the stoichiometric coefficients, which must be a positive integer.
(v) The smallest value of each variable is obtained and their values are substituted into the chemical equation. Now, a balanced chemical equation is obtained.