Question

Complete the following equations:
$i. A g+P C l_{5}$
$ii. C a F_{2}+H_{2} S O_{4}$

Answer 1

Hint: Using law of conservation of mass. We are going to solve the chemical reaction and find out its final reactant.Some of these reactions are redox reactions and can be solved by the oxidation-reduction concept.

Complete step by step answer:
(i) In order to solve this chemical reaction, let's first see what are the reactants present in the reaction $A g+P C l_{5}$
$A g $ = Silver
$P C l_{5}$ = Phosphorus Pentachloride
It's clear that reactants are silver and phosphorus pentachloride.
In chemical reaction, the amount of every element doesn't change. In this way, each side of the equation must represent an equal amount of a specific element. In case of net ionic responses, a similar charge must be available on the both sides of the unequal equation. Silver reacts with Phosphorus Pentachloride to produce Silver Chloride and Phosphorus Trichloride.
Hence The balanced chemical equations are:-
$2 A g+P C l_{5} \rightarrow 2 A g C l+P C l_{3}$
In $P C l_{5}$ oxidation state of Phosphorus (P) is +5. It cannot give electrons and cannot increase its oxidation state beyond + 5. Hence it will share its electrons and will try to reach an octet state.

(ii) In order to solve this chemical reaction, let's first see what are the reactants present in the reaction $\mathrm{CaF}_{2}+\mathrm{H}_{2} \mathrm{SO}_{4}$
$\mathrm{CaF}_{2}$=Calcium fluoride
$H_{2} S O_{4}$=sulfuric acid
It's clear that reactants are Calcium fluoride and sulfuric acid. Now during the chemical reaction
Calcium fluoride reacts with sulfuric acid to produce hydrogen fluoride and calcium sulphate.
Hence, The balanced chemical equation are:-
$\mathrm{CaF}_{2}+\mathrm{H}_{2} \mathrm{SO}_{4} \rightarrow 2 \mathrm{HF}+\mathrm{CaSO}_{4}$
Where the final products are hydrogen fluoride and calcium sulphate.

Note:
Students generally make mistakes in identifying the reactants. They will make errors while finding out the valency of atoms and will make mistakes in electron transfer during the process.