Chapter 16, Problem 3PE

(a)

Interpretation Introduction

Interpretation:

Whether the below reaction is endothermic or exothermic has to be determined.

  ${\text{SiF}}_{\text{4}}\left(g\right)+{\text{2H}}_{\text{2}}\text{O}\left(g\right)+103.8\text{ kJ}\rightleftharpoons {\text{SiO}}_{\text{2}}\left(g\right)+4\text{HF}\left(g\right)$

Concept Introduction:

The reaction that exhales energy from surrounding in form of light or heat is termed as exothermic reaction. Endothermic reactions are those that absorb energy from the environment as heat.

(b)

Interpretation Introduction

Interpretation:

On addition of $\text{HF}$ the direction of shift of equilibrium has to be determined. Also, whether molar concentration of ${\text{SiF}}_{\text{4}}$, ${\text{H}}_{\text{2}}\text{O}$, ${\text{SiO}}_{\text{2}}$ and $\text{HF}$ is increased or not in below equation has to be determined.

  ${\text{SiF}}_{\text{4}}\left(g\right)+{\text{2H}}_{\text{2}}\text{O}\left(g\right)+103.8\text{ kJ}\rightleftharpoons {\text{SiO}}_{\text{2}}\left(g\right)+4\text{HF}\left(g\right)$

Concept Introduction:

Le Chatelier’s principle states that changes at equilibrium in system respond to reduce the changes and bring back the system to restore its equilibrium under new conditions. According to this principle with increase in concentration of reactants the reaction moves towards forward direction thus this increases the concentration of products. Whereas with increase in concentration of product reaction shifts towards reverse direction. This increases the concentration of reactants.

(c)

Interpretation Introduction

Interpretation:

Addition of heat shifts equilibrium in direction that has to be determined.

Concept Introduction:

Refer to part (b).