For the reaction PC15 (8) PC13 (g) + Cl2 (g) K = 0.0454 at 261 °C. If a vessel is filled with these gases such that the initial concentrations are [PC15) = 0.20 M, [PC13] = 0.20 M, and (Cl21 = 2.5 M, in which direction will a reaction occur and why? A) toward products because Qc = 0.56 B) toward reactants because Qc = 2.5 C) toward products because Qc = 2.8 D) toward reactants because Qc = 0.0454 E) it is at equilibrium because Qc = 1

Respuesta :

Answer:

The correct answer is B.

The [tex]K_{eq}[/tex] is samller than [tex]Q[/tex] of the reaction . So,the reaction will shift towards the left i.e. towards the reactant side.

Explanation:

Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as [tex]K_{eq}[/tex]

K is the constant of a certain reaction when it is in equilibrium, while Q is the quotient of activities of products and reactants at any stage other than equilibrium of a reaction.

For the given chemical reaction:

[tex]PCl_5(g)\rightleftharpoons PCl_3(g)+Cl_2(g)[/tex]

The expression for [tex]Q[/tex] is written as:

[tex]Q=\frac{[PCl_3][Cl_2]}{[[PCl_5]^1}[/tex]

[tex]Q=\frac{0.20 M\times 2.5 M}{0.20 M}[/tex]

[tex]Q=2.5[/tex]

Given : [tex]K_{eq}[/tex] = 0.0454

Thus as [tex]K_{eq}<Q[/tex], the reaction will shift towards the left i.e. towards the reactant side.

Answer: The reaction proceed toward reactants because [tex]Q_c[/tex] is 2.5

Explanation:

[tex]K_c[/tex] is the constant of a certain reaction at equilibrium while [tex]Q_c[/tex] is the quotient of activities of products and reactants at any stage other than equilibrium of a reaction.

For the given chemical reaction:

[tex]PCl_5(g)\rightleftharpoons PCl_3(g)+Cl_2(g)[/tex]

The expression of [tex]Q_c[/tex] for above equation follows:

[tex]Q_c=\frac{[PCl_3][Cl_2]}{[PCl_5]}[/tex]

We are given:

[tex][PCl_3]=0.20M[/tex]

[tex][Cl_2]=2.5M[/tex]

[tex][PCl_5]=0.20M[/tex]

Putting values in above equation, we get:

[tex]Q_c=\frac{0.20\times 2.5}{0.20}=2.5[/tex]

We are given:

[tex]K_c=0.0454[/tex]

There are 3 conditions:

  • When [tex]K_{c}>Q_c[/tex]; the reaction is product favored.
  • When [tex]K_{c}<Q_c[/tex]; the reaction is reactant favored.
  • When [tex]K_{c}=Q_c[/tex]; the reaction is in equilibrium.

As, [tex]Q_c>K_c[/tex], the reaction will be favoring reactant side.

Hence, the reaction proceed toward reactants because [tex]Q_c[/tex] is 2.5