An equilibrium that would favour the products is
A. NH4+(aq) + H2PO4-(aq)= NH3(aq) + H3PO4(aq)
B. HCN(aq) + HS-(aq)= CN-(aq) + H2S(aq)
C. HCO3-(aq) +,HBO3 2-(aq)= H2BO3-(aq) + CO3 2-(aq)
D. HSO4-(aq) + HSO3-(aq)= H2SO3(aq) + SO4 2- (aq)
The answer is C. But I don't understand why.
Any help would be greatly appreciated
To determine which equilibrium favors the products, we need to analyze the equilibrium constant (K) expression for each reaction. The general form of a chemical equilibrium equation is:
aA + bB ⇌ cC + dD
The equilibrium constant expression for this reaction would be:
K = ([C]^c[D]^d) / ([A]^a[B]^b)
Let's evaluate each option using this information:
A. NH4+ + H2PO4- ⇌ NH3 + H3PO4
Equilibrium constant expression: [NH3][H3PO4] / [NH4+][H2PO4-]
In this case, the dissociation of NH4+ and H2PO4- is weaker compared to the formation of NH3 and H3PO4. Therefore, this equilibrium favors the reactants, rather than the products.
B. HCN + HS- ⇌ CN- + H2S
Equilibrium constant expression: [CN-][H2S] / [HCN][HS-]
Similarly, the formation of HCN and HS- is stronger compared to the formation of CN- and H2S. Thus, this equilibrium also favors the reactants.
C. HCO3- + H2BO3- ⇌ H2BO3- + CO32-
Equilibrium constant expression: [H2BO3-][CO32-] / [HCO3-][H2BO3-]
In this case, notice that the H2BO3- appears on both sides of the equation, so it cancels out. The equilibrium constant expression simplifies to [CO32-] / [HCO3-].
Since the equilibrium constant expression does not include H2BO3-, it means that its formation does not affect the equilibrium. Therefore, this equilibrium favors the products (CO32-) over the reactant (HCO3-).
D. HSO4- + HSO3- ⇌ H2SO3 + SO42-
Equilibrium constant expression: [H2SO3][SO42-] / [HSO4-][HSO3-]
While H2SO3 is a weak acid, it is still stronger compared to the formation of HSO4- and HSO3-. Hence, this equilibrium favors the reactants.
Based on the analysis, the equilibrium that would favor the products is C. HCO3- + H2BO3- ⇌ H2BO3- + CO32-.
To determine which of the given reactions would favor the products, we need to consider the principles of Le Chatelier's principle and the equilibrium constant (K).
Le Chatelier's principle states that if a system at equilibrium is subjected to a change, it will respond by shifting in a way that minimizes the effect of the change. In the context of chemical reactions, this means that if we add or remove reactants or products, the equilibrium position will shift towards the side where the change occurred to re-establish equilibrium.
The equilibrium constant, denoted as K, is a measure of the relative amounts of products and reactants at equilibrium. A high value of K indicates that the products are favored, while a low value of K indicates that the reactants are favored.
Let's analyze each of the given reactions and determine which one will favor the products:
A. NH4+(aq) + H2PO4-(aq) = NH3(aq) + H3PO4(aq)
The presence of two positively charged ions (NH4+ and H2PO4-) and two negatively charged ions (NH3 and H3PO4) makes it difficult to predict the direction of the equilibrium shift. Additionally, we don't have any information about the concentrations or relative stability of the substances involved, so we cannot determine the favoring of products based on this information.
B. HCN(aq) + HS-(aq) = CN-(aq) + H2S(aq)
Similar to reaction A, we have both positively charged (HCN and H2S) and negatively charged (CN- and HS-) species. Without additional information, we cannot determine the favoring of products.
C. HCO3-(aq) + HBO3 2-(aq) = H2BO3-(aq) + CO3 2-(aq)
This reaction involves the formation of two negatively charged ions, H2BO3- and CO3 2-. According to Le Chatelier's principle, if we remove any of the products, the system will shift towards the production of more products to compensate. Therefore, this reaction would favor the products.
D. HSO4-(aq) + HSO3-(aq) = H2SO3(aq) + SO4 2-(aq)
In this reaction, we have both positively charged (HSO4- and H2SO3) and negatively charged (HSO3- and SO4 2-) species. Similarly to reactions A and B, we cannot predict the favoring of products without additional information.
From the analysis above, it appears that the equilibrium in reaction C (HCO3-(aq) + HBO3 2-(aq) = H2BO3-(aq) + CO3 2-(aq)) would favor the products.