Chapter 3, Problem 3.6P

(a)

Interpretation Introduction

Interpretation:

Chemical equation given below has to be balanced and name of reactants and products has to be given.

    ${\text{PCl}}_{\text{3}}(g)+{\text{Cl}}_{\text{2}}(g)\to {\text{PCl}}_{\text{5}}(s)$

Concept Introduction:

Chemical reaction is represented in short form by using the molecular formulas of products and reactants in which an arrow is present between reactants and products is known as chemical equation.  Atoms are neither created nor destroyed in any chemical reaction.  Therefore, the resulting chemical equation written for the chemical reaction should also be balanced.

Steps followed to obtain balanced chemical equation:

• Chemical formulas of the products and reactants are written.  Individual reactants and products are separated using plus sign while the reactants are separated from products by an arrow.
• Elements that appear only once on the reactant side and product side is balanced first.  Subscript should not be changed in chemical formula while balancing coefficients can be added until the total number of atoms of an element becomes equal on reactant and product side.
• Other elements present also balanced in the same way by adding balancing coefficients.
• Final check has to be performed in order to check that each element that is present in the chemical equation is balanced.
• Symbols have to be added for solids, liquids gases and aqueous solutions to indicate the physical state of the known reactants and products.

Explanation of Solution

Chemical equation given is shown below.

    ${\text{PCl}}_{\text{3}}(g)+{\text{Cl}}_{\text{2}}(g)\to {\text{PCl}}_{\text{5}}(s)$

The above equation has equal number of atoms of same element on both sides of the equation.  Therefore, this is a self-balanced chemical equation.

    ${\text{PCl}}_{\text{3}}(g)+{\text{Cl}}_{\text{2}}(g)\to {\text{PCl}}_{\text{5}}(s)(balanced)$

Name of the reactants and products can be given as shown below.

    $\begin{array}{l}{\text{PCl}}_{\text{3}}\text{-}\text{Phosphorus trichloride}\\ {\text{Cl}}_{\text{2}}\text{-}\text{Chlorine}\\ {\text{PCl}}_{\text{5}}\text{-}\text{Phosphorus pentachloride}\end{array}$

(b)

Interpretation Introduction

Interpretation:

Chemical equation given below has to be balanced and name of reactants and products has to be given.

    $\text{Sb}(s)+{\text{Cl}}_{\text{2}}(g)\to {\text{SbCl}}_{\text{3}}(s)$

Concept Introduction:

Refer part (a).

Explanation of Solution

Chemical equation given is shown below.

    $\text{Sb}(s)+{\text{Cl}}_{\text{2}}(g)\to {\text{SbCl}}_{\text{3}}(s)$

In the above equation there are two chlorine atoms on the reactant side but three chlorine atoms are present on the product side.  Adding coefficient $3$ before ${\text{Cl}}_{\text{2}}$ in the reactant side and coefficient $2$ before ${\text{SbCl}}_{\text{3}}$ in the product side balances the chlorine atom.  Therefore, the chemical equation can be given as shown below.

    $\text{Sb}(s)+3{\text{Cl}}_{\text{2}}(g)\to 2{\text{SbCl}}_{\text{3}}(s)(notbalanced)$

In the above equation, there is one antimony atom on the reactant side but two antimony atoms on the product side.  Adding coefficient $2$ before $\text{Sb}$ in the reactant side balances the antimony atom on both sides.  The balanced chemical equation is given as shown below.

    $\text{2Sb}(s)+3{\text{Cl}}_{\text{2}}(g)\to 2{\text{SbCl}}_{\text{3}}(s)(balanced)$

Name of the reactants and products can be given as shown below.

    $\begin{array}{l}\text{Sb}\text{-}\text{Antimony}\\ {\text{Cl}}_{\text{2}}\text{-}\text{Chlorine}\\ {\text{SbCl}}_{\text{3}}\text{-}\text{Antimony trichloride}\end{array}$

(c)

Interpretation Introduction

Interpretation:

Chemical equation given below has to be balanced and name of reactants and products has to be given.

    ${\text{GaBr}}_{\text{3}}(s)+{\text{Cl}}_{\text{2}}(g)\to {\text{GaCl}}_{\text{3}}(s)+{\text{Br}}_{\text{2}}(l)$

Concept Introduction:

Refer part (a).

Explanation of Solution

Chemical equation given is shown below.

    ${\text{GaBr}}_{\text{3}}(s)+{\text{Cl}}_{\text{2}}(g)\to {\text{GaCl}}_{\text{3}}(s)+{\text{Br}}_{\text{2}}(l)$

In the above equation there are two chlorine atoms in the reactant side but three chlorine atoms in the product side.  Adding coefficient $3$ before ${\text{Cl}}_{\text{2}}$ in the reactant side and $2$ before ${\text{GaCl}}_{\text{3}}$ on the product side balances the chlorine atom.  The chemical equation obtained is given below.

    ${\text{GaBr}}_{\text{3}}(s)+3{\text{Cl}}_{\text{2}}(g)\to 2{\text{GaCl}}_{\text{3}}(s)+{\text{Br}}_{\text{2}}(l)(notbalanced)$

In the above equation there are three bromine atoms in the reactant side but two bromine atoms in the product side.  Adding coefficient $2$ before ${\text{GaBr}}_{\text{3}}$ in the reactant side and $3$ before ${\text{Br}}_{\text{2}}$ on the product side balances the bromine atom.  The balanced chemical equation obtained is given below.

    ${\text{2GaBr}}_{\text{3}}(s)+3{\text{Cl}}_{\text{2}}(g)\to 2{\text{GaCl}}_{\text{3}}(s)+3{\text{Br}}_{\text{2}}(l)(balanced)$

Name of the reactants and products can be given as shown below.

    $\begin{array}{l}{\text{GaBr}}_{\text{3}}\text{-}\text{Gallium bromide}\\ {\text{Cl}}_{\text{2}}\text{-}\text{Chlorine}\\ {\text{GaCl}}_{\text{3}}\text{-}\text{Gallium chloride}\\ {\text{Br}}_{\text{2}}\text{-}\text{Bromine}\end{array}$

(d)

Interpretation Introduction

Interpretation:

Chemical equation given below has to be balanced and name of reactants and products has to be given.

    ${\text{Mg}}_{\text{3}}{\text{N}}_{\text{2}}(s)+\text{HCl}(g)\to {\text{MgCl}}_{\text{2}}(s)+{\text{NH}}_{\text{3}}(g)$

Concept Introduction:

Refer part (a).

Explanation of Solution

Chemical equation given is shown below.

    ${\text{Mg}}_{\text{3}}{\text{N}}_{\text{2}}(s)+\text{HCl}(g)\to {\text{MgCl}}_{\text{2}}(s)+{\text{NH}}_{\text{3}}(g)$

In the above equation there are three magnesium atoms in the reactant side but only one magnesium atom in the product side.  Adding coefficient $3$ before ${\text{MgCl}}_{\text{2}}$ in the product side balances the magnesium atom.  The chemical equation obtained is given below.

    ${\text{Mg}}_{\text{3}}{\text{N}}_{\text{2}}(s)+\text{HCl}(g)\to 3{\text{MgCl}}_{\text{2}}(s)+{\text{NH}}_{\text{3}}(g)(notbalanced)$

In the above equation there are six chlorine atoms the product side but only one chlorine atom in the reactant side.  Adding coefficient $6$ before $\text{HCl}$ in the reactant side balances the chlorine atom.  The chemical equation obtained is given below.

    ${\text{Mg}}_{\text{3}}{\text{N}}_{\text{2}}(s)+6\text{HCl}(g)\to 3{\text{MgCl}}_{\text{2}}(s)+{\text{NH}}_{\text{3}}(g)(notbalanced)$

In the above equation there are three hydrogen atoms the product side but six hydrogen atoms are present in the reactant side.  Adding coefficient $2$ before ${\text{NH}}_{\text{3}}$ in the product side balances the hydrogen atom.  The balanced chemical equation obtained is given below.

    ${\text{Mg}}_{\text{3}}{\text{N}}_{\text{2}}(s)+6\text{HCl}(g)\to 3{\text{MgCl}}_{\text{2}}(s)+2{\text{NH}}_{\text{3}}(g)(balanced)$

Name of the reactants and products can be given as shown below.

    $\begin{array}{l}{\text{Mg}}_{\text{3}}{\text{N}}_{\text{2}}\text{-}\text{Magnesium nitride}\\ \text{HCl}\text{-}\text{Hydrogen chloride}\\ {\text{MgCl}}_{\text{2}}\text{-}\text{Magnesium chloride}\\ {\text{NH}}_{\text{3}}\text{-}\text{Ammonia}\end{array}$