A cleaning solution is used to remove limescale, CaCO3, from bathroom surfaces. When the solution is sprayed onto the limescale, effervescence (fizzing) occurs and the solid limescale begins to disappear. This chemical reaction is needed because the limescale cannot be removed with water alone. Which of the following statements about this chemical reaction are correct? 1. The cleaning solution is acidic. 2. The effervescence (fizzing) is caused by the release of hydrogen gas. 3. The pH of the reacting solution will go down as the reaction proceeds. 4. The salt produced in the reaction is more soluble than CaCO3

Explanation

Statements 1,3 are correct. Based on the information provided, the correct statements about this chemical reaction are: The cleaning solution is acidic. The pH of the reacting solution will go down as the reaction proceeds. Explanation: The cleaning solution being acidic is likely the reason why it can dissolve limescale (CaCO3). Acidic solutions can react with and dissolve calcium carbonate, breaking it down into soluble products. The effervescence (fizzing) occurs due to the reaction between the acidic solution and calcium carbonate. When an acid reacts with a carbonate compound like CaCO3, it releases carbon dioxide (CO2) gas, which causes the fizzing. As the reaction proceeds and the acidic solution reacts with the limescale (CaCO3), it will produce carbon dioxide gas and water. The presence of carbon dioxide in the solution can lead to the formation of carbonic acid (H2CO3) by combining with water. This carbonic acid can further contribute to the acidic nature of the solution, leading to a decrease in pH. However, statement 4 cannot be determined based on the information provided. The given information does not mention the specific salt produced in the reaction, nor does it provide any details about its solubility compared to CaCO3.