Question

Write a balanced chemical equation for the reaction of red lead (trilead tetraoxide) warmed with concentrated $HCl$ .
(A) $2P{b_3}{O_4} + 16HCl \to 6PbCl + 8{H_2}O + 5C{l_2}$
(B) $P{b_3}{O_4} + 16HCl \to 3PbCl + 8{H_2}O + 5C{l_2}$
(C) $2P{b_3}{O_4} + 8HCl \to 6PbCl + 4{H_2}O + 5C{l_2}$
(D) $2P{b_3}{O_4} + 8HCl \to 6PbCl + 4{H_2}O + C{l_2}$

Answer 1

Hint : When red lead is heated with concentrated hydrochloric acid it produces lead chloride, water and chlorine. According to the law of mass conservation, total mass in a system is conserved that’s why the number of a particular element is the same on reactant and product side.

Complete Step By Step Answer:
Balanced chemical equation- A chemical equation that correctly depict the number of atoms on reactant and product side of reaction that is atoms of a particular element is equal on both sides. So that the equation follows the law of conservation of mass, the mass will remain conserved in all types of chemical reactions except nuclear reactions. In nuclear reactions some mass is converted into energy that’s why they do not follow the law of mass conservation.
Chemical formula of red lead is $P{b_3}{O_4}$
Red lead when heated in presence of concentrated $HCl$ the products are lead chloride, water and chlorine. Thus the reaction can be shown as-
$P{b_3}{O_4} + HCl \to PbCl + {H_2}O + C{l_2}$
In the above equation the number of atoms on reactant and product sides are not equal. So we have to balance the equation. Thus the balance equation is-
$2P{b_3}{O_4} + 16HCl \to 6PbCl + 8{H_2}O + 5C{l_2}$
That equation correctly depicts the number of atoms on both sides hence it is a balance equation. The numbers before reagents are known as stoichiometric coefficient. It shows that two moles of $P{b_3}{O_4}$
Required $16$ moles of hydrochloric acid to completely react to produce $6$ moles of lead chloride and $8$ moles of water and $5$ moles of chlorine gas.
Hence option (A) is the correct answer.

Note :
The calculations based on balanced chemical equations are known as stoichiometric calculations. In this reaction $PbC{l_2}$ is also formed when red lead reacts with hydrochloric acid present in a limited amount.