What are the generalisations concerning the direction of reaction from the value of reaction quotient and equilibrium constant?
Answers
Answer:
constant is
All other factors affecting the rate—temperature and catalyst presence, for example—are included in the rate constant, which is only constant if the only change is in the concentration of the reactants. If the temperature is changed or a catalyst is added, for example, the rate constant changes...
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The generalization concerning the direction of reaction from the value of reaction quotient and equilibrium constant
Explanation:
Law of mass action
It states that: Rate of a reaction is directly proportional to concentration of reactants raised to their respective moles.
Consider a reaction: aA + bB --> nC + xD
Or, R =K[A]ᵃ[B]ᵇ
Where ‘K’ is rate constant or velocity constant
At equilibrium: Rate of forward reaction = rate of backward reaction
That is: Kf[A]ᵃ[B]ᵇ = Kb[C] ⁿ[D]ˣ
But, Kc=Kf/Kb (where Kc is equilibrium constant)
Kc = [A]ᵃ[B]ᵇ/[C]ⁿ[D]ˣ
At particular instant of time: The equilibrium constant is called as reaction quotient (Q).
That is: Q=[C]ⁿ[D]ˣ / [A]ᵃ[B]ᵇ
At equilibrium Q=Kc
Application of Equilibrium constant
1. Predicting the extent of reaction: The equilibrium constant is directly proportional to extent of reaction.
• If value of k is large, the reaction goes in forward reaction.
• If value of k is less, the reaction goes in backward reaction.
• If k>10³, the extent in this case is large and a reaction proceed almost to completion.
• If value of k is less than 10⁻³, then the reaction proceeds to smaller extent.
• If value of k is between 10⁻³ to 10³, then there is a appreciable concentration of reactants and products.
2. Predicting the direction of reaction: It tells us whether the reaction is going towards product or reactant. Reaction quotient = Q.
• If Q<k, then reactants predominate.
• If Q=k, then the reaction is at equilibrium.
• If Q>k, then the products predominate.
3. Calculation of equilibrium constant and concentrations.
K= [Products]/ [Reactants]
2. Predicting the direction of reaction: It tells us whether the reaction is going towards product or reactant. Reaction quotient = Q.
2. Predicting the direction of reaction: It tells us whether the reaction is going towards product or reactant. Reaction quotient = Q.