Chapter 12, Problem 65A

(a)

Interpretation Introduction

Interpretation: The balanced equation for the reaction is to be written.

Concept Introduction: A chemical process in which electrons are moved between two reactants is referred to as a redox reaction. The redox reactions include combination reactions, combustion reactions, decomposition reactions, and single-replacement reactions.

Answer to Problem 65A

The balanced equation for the reaction is as follows:

  ${\text{H}}_2+{\text{I}}_{\text{2}}\to \text{2HI}$

Explanation of Solution

Hydrogen gas and iodine vapor react to give gaseous hydrogen iodide.

  ${\text{H}}_2+{\text{I}}_{\text{2}}\to \text{2HI}$

The above equation is the balanced equation for the reaction.

(b)

Interpretation Introduction

Interpretation: The limiting reagent in the reactant is to be identified.

Concept Introduction: A chemical process in which electrons are moved between two reactants is referred to as a redox reaction. The redox reactions include combination reactions, combustion reactions, decomposition reactions, and single-replacement reactions.

Answer to Problem 65A

Iodine vapor is the limiting reagent.

Explanation of Solution

The reactant that limits how much product can be produced by a reaction is known as the limiting reagent. Only until the limiting reagent is consumed does the reaction take place.

Hydrogen gas and iodine vapor react to give gaseous hydrogen iodide.

  ${\text{H}}_2+{\text{I}}_{\text{2}}\to \text{2HI}$

From the figure, it is clear that the number of molecules of hydrogen remains in excess after reacting with iodine. Hydrogen gas is the excess reactant.

Iodine vapor is the limiting reagent since the molecules are in the lesser molecule when compared with hydrogen gas.

(c)

Interpretation Introduction

Interpretation: The number of molecules of the reagent in the excess that remain at the completion of the reaction is to be calculated.

Concept Introduction: A chemical process in which electrons are moved between two reactants is referred to as a redox reaction. The redox reactions include combination reactions, combustion reactions, decomposition reactions, and single-replacement reactions.

Answer to Problem 65A

The number of molecules of the reagent is three molecules of hydrogen gas.

Explanation of Solution

Hydrogen gas and iodine vapor react to give gaseous hydrogen iodide.

  ${\text{H}}_2+{\text{I}}_{\text{2}}\to \text{2HI}$

Iodine vapor is the limiting reagent.

The reaction occurs only till all the iodine vapor reacts with hydrogen gas.

There is four iodine vapor that has reacted with four hydrogen gas. So, the remaining molecules of hydrogen gas are three molecules.

(d)

Interpretation Introduction

Interpretation: The number of molecules of the limiting reagent needed to be added to the atomic window so that all the reactants will react to form products is to be calculated.

Concept Introduction: A chemical process in which electrons are moved between two reactants is referred to as a redox reaction. The redox reactions include combination reactions, combustion reactions, decomposition reactions, and single-replacement reactions.

Answer to Problem 65A

Three molecules of the limiting reagent iodine vapor are needed.

Explanation of Solution

Hydrogen gas and iodine vapor react to give gaseous hydrogen iodide.

  ${\text{H}}_2+{\text{I}}_{\text{2}}\to \text{2HI}$

Iodine vapor is the limiting reagent.

The reaction occurs only till all the iodine vapor reacts with hydrogen gas.

There is four iodine vapor that has reacted with four hydrogen gas. So, the remaining molecules of hydrogen gas are three molecules.

There is a need for three molecules of iodine vapor to react with excess hydrogen gas.