Question

Complete the following equations
1.${\text{S}} + {{\text{H}}_2}{\text{S}}{{\text{O}}_4} \to$
2.${\text{PC}}{{\text{l}}_3} + {{\text{H}}_2}{\text{O}} \to$

Answer 1

On the reactant and product sides of a balanced chemical equation, there are equivalent numbers of atoms for each element involved in the reaction. This is a condition that the equation must meet in order to be consistent with the conservation of matter law.

Complete answer:
1.${\text{S}} + {{\text{H}}_2}{\text{S}}{{\text{O}}_4} \to {\text{S}}{{\text{O}}_2} + {{\text{H}}_2}{\text{O}}$
The chemical compound sulphur dioxide has the formula$S{O_2}$. It's a poisonous gas that gives off the odour of burned matches. It is created as a by-product of copper mining and the burning of sulfur-contaminated fossil fuels, and it is released spontaneously by volcanic activity. The odour of sulphur dioxide is similar to that of nitric acid.
To balance, we take oxygen first

Atom	LHS	RHS	Factor multiplied	LHS	RHS
S	2	1	3	3	3
H	2	2	2	4	4
O	4	3	3 in $S{O_2}$2 in ${H_2}O$	8	8

Balanced equation is ${\text{S}} + 2{{\text{H}}_2}{\text{S}}{{\text{O}}_4} \to 3{\text{S}}{{\text{O}}_2} + 2{{\text{H}}_2}{\text{O}}$
2.${\text{PC}}{{\text{l}}_3} + {{\text{H}}_2}{\text{O}} \to {{\text{H}}_3}{\text{P}}{{\text{O}}_3} + {\text{HCl}}$
The gradual burning of phosphorus produces phosphoric acid, which is a white volatile powder. The salts it produces are known as phosphites. Allowing phosphorus trichloride to react with water is a simple way to make it. $PC{l_3}$is sprayed into steam at 190⁰C in industrial synthesis, and the heat of reaction is used to distil off the hydrogen chloride and waste water vapour.
To balance, we take oxygen first

Atom	LHS	RHS	Factor multiplied	LHS	RHS
P	1	1	1	1	1
Cl	3	1	3 in HCl	3	3
H	2	4	3	6	6
O	1	3	3 in ${H_3}P{O_3}$	3	3

Balanced equation is ${\text{PC}}{{\text{l}}_3} + 3{{\text{H}}_2}{\text{O}} \to {{\text{H}}_3}{\text{P}}{{\text{O}}_3} + 3{\text{HCl}}$

Note:
According to this rule, the total mass of the components remains proportional to the total mass of the reactants after any physical or chemical transition.
"Matter is neither produced nor destroyed in a chemical reaction," to put it another way. The "law of indestructibility of matter" is another name for the law of conservation of mass.