Chapter 11, Problem 62A

(a)

Interpretation Introduction

Interpretation: The given reaction needs to be completed and balanced.

Concept Introduction: A chemical reaction is said to be balanced if there are same number of atoms of the same elements on both sides of the reaction arrow.

Explanation of Solution

The given reaction can be completed as follows:

  $\text{K}\left(s\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)\to \text{KOH}\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)$

In the above reaction, the number of hydrogen atoms are not balanced.

The above reaction can be balanced by giving coefficient 2 to $\text{K}\left(s\right)$ , ${\text{H}}_{\text{2}}\text{O}\left(l\right)$ and $\text{KOH}\left(aq\right)$ .

  $\text{2K}\left(s\right)+2{\text{H}}_{\text{2}}\text{O}\left(l\right)\to 2\text{KOH}\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)$

Therefore, the above reaction is complete and balanced.

(b)

Interpretation Introduction

Interpretation: The given reaction needs to be completed and balanced.

Concept Introduction: A chemical reaction is said to be balanced if there are same number of atoms of the same elements on both sides of the reaction arrow.

Explanation of Solution

The given reaction can be completed as follows:

  ${\text{C}}_{\text{2}}{\text{H}}_{\text{5}}\text{OH}\left(l\right)+{\text{O}}_{\text{2}}\left(g\right)\to {\text{CO}}_2\left(g\right)+{\text{H}}_{\text{2}}\text{O}\left(g\right)$

In the above reaction, C and H atoms are not balanced. To balance the number of C atoms, give coefficient 2 to ${\text{CO}}_2\left(g\right)$ .

  ${\text{C}}_{\text{2}}{\text{H}}_{\text{5}}\text{OH}\left(l\right)+{\text{O}}_{\text{2}}\left(g\right)\to 2{\text{CO}}_2\left(g\right)+{\text{H}}_{\text{2}}\text{O}\left(g\right)$

Now, give coefficient 3 to ${\text{H}}_{\text{2}}\text{O}\left(g\right)$ to balance the number of H atoms.

  ${\text{C}}_{\text{2}}{\text{H}}_{\text{5}}\text{OH}\left(l\right)+{\text{O}}_{\text{2}}\left(g\right)\to 2{\text{CO}}_2\left(g\right)+3{\text{H}}_{\text{2}}\text{O}\left(g\right)$

Give coefficient 3 to ${\text{O}}_{\text{2}}\left(g\right)$ to balance the number of O atoms.

  ${\text{C}}_{\text{2}}{\text{H}}_{\text{5}}\text{OH}\left(l\right)+3{\text{O}}_{\text{2}}\left(g\right)\to 2{\text{CO}}_2\left(g\right)+3{\text{H}}_{\text{2}}\text{O}\left(g\right)$

The above chemical reaction is complete and balanced.

(c)

Interpretation Introduction

Interpretation: The given reaction needs to be completed and balanced.

Concept Introduction: A chemical reaction is said to be balanced if there are same number of atoms of the same elements on both sides of the reaction arrow.

Explanation of Solution

The given reaction can be completed as follows:

  $\text{Bi}{\left({\text{NO}}_{\text{3}}\right)}_3\left(aq\right){\text{+H}}_{\text{2}}\text{S}\left(l\right)\to {\text{Bi}}_{\text{2}}{\text{S}}_{\text{3}}\left(s\right)+{\text{HNO}}_{\text{3}}\left(aq\right)$

To balance the above reaction, give coefficient 2 to $\text{Bi}{\left({\text{NO}}_{\text{3}}\right)}_3$ , 6 to ${\text{HNO}}_{\text{3}}\left(aq\right)$ and 3 to ${\text{H}}_{\text{2}}\text{S}\left(l\right)$

  $\text{2Bi}{\left({\text{NO}}_{\text{3}}\right)}_3\left(aq\right){\text{+3H}}_{\text{2}}\text{S}\left(l\right)\to {\text{Bi}}_{\text{2}}{\text{S}}_{\text{3}}\left(s\right)+6{\text{HNO}}_{\text{3}}\left(aq\right)$

Therefore, the above reaction is complete and balanced.

(d)

Interpretation Introduction

Interpretation: The given reaction needs to be completed and balanced.

Concept Introduction: A chemical reaction is said to be balanced if there are same number of atoms of the same elements on both sides of the reaction arrow.

Explanation of Solution

The given reaction is as follows:

  $\text{Al}\left(s\right)+{\text{Br}}_2\left(l\right)\to {\text{AlBr}}_{\text{3}}\left(s\right)$

To balance the above reaction, give coefficient 2 to $\text{Al}\left(s\right)$ , 3 to ${\text{Br}}_2\left(l\right)$ and 2 to ${\text{AlBr}}_{\text{3}}\left(s\right)$ .

  $\text{2Al}\left(s\right)+3{\text{Br}}_2\left(l\right)\to 2{\text{AlBr}}_{\text{3}}\left(s\right)$

Therefore, the above reaction is complete and balanced.