The oxidation of iodide ions by arsenic acid in acidic aqueous solution occurs according to the net reaction H3AsO4 + 3I – + 2 H3O +→ H3AsO3 + I3– + H2O. The experimental rate law for this reaction is
Rate = k [H3AsO4] [I–] [H3O+].
According to the rate law for the reaction, an increase in the concentration of hydronium ion has what effect on this reaction?
The rate is increased and the equilibrium is shifted to the right.
Well, let me tell you, when it comes to this reaction, the hydronium ions are like the divas of the party. When their concentration increases, they start demanding all the attention and stealing the show. So, an increase in the concentration of hydronium ion would definitely speed up the reaction. It's like giving the reaction a caffeine boost, making it go faster than an Olympic runner on roller skates!
According to the rate law for the reaction, an increase in the concentration of hydronium ion, [H3O+], will have a direct effect on the rate of the reaction. Specifically, an increase in the concentration of hydronium ion will cause an increase in the rate of the reaction.
This is because the rate law states that the rate of the reaction is directly proportional to the concentration of hydronium ion. Therefore, if the concentration of hydronium ion increases, the rate of the reaction will also increase. Conversely, if the concentration of hydronium ion decreases, the rate of the reaction will decrease.
According to the given rate law, an increase in the concentration of hydronium ion ([H3O+]) will have a direct impact on the reaction rate. Specifically, increasing the concentration of hydronium ion will result in an increase in the rate of the reaction.
To understand why this is the case, we need to consider the reaction mechanism and how the hydronium ion participates in the reaction.
In the net reaction, H3AsO4 (arsenic acid) is oxidized to H3AsO3, and I- (iodide ion) is oxidized to I3- (triiodide ion). This reaction occurs in an acidic aqueous solution, meaning that there is an excess of hydronium ions (H3O+) present.
The hydronium ion acts as a catalyst in the reaction, facilitating the oxidation of iodide ions by arsenic acid. It accomplishes this by providing H+ ions, which can react with the iodide ions and help form the triiodide ion.
Therefore, an increase in the concentration of hydronium ion will lead to an increase in available H+ ions, resulting in a higher likelihood of reaction between the hydronium ion and the iodide ions. As a result, more triiodide ion will be formed, and the rate of the overall reaction will increase.
To summarize, increasing the concentration of hydronium ion has a direct effect on the reaction rate in this case, as it acts as a catalyst by providing H+ ions that react with the iodide ions during the oxidation process.