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
Correct answer: C. 1 and 4 only
- A. 1 and 2 only
- B. 1 and 3 only
- C. 1 and 4 only
- D. 2 and 3 only
- E. 2 and 4 only
- F. 1, 3 and 4
Explanation
The correct answer is C, which means that only statements 1 and 4 are correct.Statement 1 is correct because limescale is composed of calcium carbonate (CaCO3), which is a base, and an acid-based cleaning solution is needed to react with it. The acid in the cleaning solution can neutralize the base and break down the limescale.Statement 2 is incorrect because the effervescence is caused by the release of carbon dioxide gas, not hydrogen gas. When an acid reacts with a carbonate, carbon dioxide gas is produced as a byproduct, which is what causes the effervescence.Statement 3 is incorrect because the pH of the reacting solution will not actually decrease as the reaction proceeds.Statement 4 is correct because the salt produced in the reaction, calcium acetate (Ca(CH3COO)2), is more soluble than CaCO3. This means that it can dissolve in water more easily, allowing it to be rinsed away along with the limescale.Therefore, the correct answer is C, which includes only statements 1 and 4 as correct.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About Scientific Reasoning
Scientific reasoning evaluates hypotheses through observations, variables, controls, measurements and experimental results. Questions involve identifying independent and dependent variables, recognising a fair test, interpreting tables or graphs, distinguishing evidence from opinion, and deciding whether data supports, rejects or leaves a hypothesis unresolved.
Practise Scientific Reasoning
334 free Scientific Reasoning MCQs from Analytical and Logical Reasoning, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Analytical and Logical Reasoning questions like this
Analytical and Logical Reasoning is on 27 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Scientific Reasoning questions
The price for hiring a car is determined by the number of days for which it is to be hired and the number of people who will be using it. The table below shows the prices for groups of up to 5 people hiring cars for up to 7 days. Patrick is part of a group of 5 people on a holiday for 5 days. They will be going on outings each day, and had planned to hire one car for all of them for all 5 days. However, two of the group of people will only be there for the first 3 days, so an alternative is to hire one car for this period and another for the final two days. What will be the difference if they choose this alternative?
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
A dice is numbered from 1 to 6 in different ways. If 1 is adjacent to 2, 4, and 6, then which of the following statements is necessarily true?
In a restaurant recently, I received the following bill: Starter $7.00 Main Course $20.75 Dessert $9.75 Drink $4.50 Service Charge $5.25 TOTAL $47.25 What percentage of the cost of the food and drink had been added to the bill as service charge?
A recipe for tarte Tatin requires: 500g pastry 800g apples 100 g caster sugar 100 ml apple juice 6g of vanilla 50 g of butter Amber, Bekim, Cairo, and Darcy have the following quantities of each ingredient: The quantity is given in the image below Who can make the largest tarte Tatin?
Many people were worried when they found that their photocopiers had been sometimes changing numbers; one photocopier sometimes, although not always, changed 6 into 8. A list of prices was copied on this photocopier. The first five prices on the copy·are shown below. $54.80 $60.00 $65.40 $70.80 $78.20 In the original list, the prices had increased by the same amount each time. What was the next price.on the original list?