Final answer:
Higher concentrations of NaOH react faster with CO₂ due to more hydroxide ions being available to react, thus increasing the rate of reaction. Conversely, lower concentrations of NaOH result in a slower reaction. The mixture of vinegar and baking soda decreases pH levels because of acid formation.
Step-by-step explanation:
The different concentrations of NaOH in each of the wells take a different amount of time to react with CO₂ because reaction rate is influenced by the concentration of the reactants. According to the chemical equation CO₂ (aq) + 2NaOH(aq) → Na₂CO₃(aq) + H₂O(l), two moles of NaOH are required to react with one mole of CO₂. A higher concentration of NaOH will have more hydroxide ions available to react with the CO₂, which increases the rate of reaction. The reaction occurs faster as the concentration of NaOH increases. Conversely, lower concentrations of NaOH have fewer hydroxide ions available, slowing down the rate of reaction.
When vinegar and baking soda are mixed, they undergo a chemical reaction that produces CO₂ as a byproduct, resulting in a decrease in pH, making the solution more acidic due to the formation of acetic and carbonic acids.