Let's analyze the information step by step to determine the pH of solution Y and identify what solution Y is.
### Part (a): Suggest the pH of solution Y
Observations:
- Universal indicator paper turned blue.
Analysis for pH:
- Universal indicator paper turning blue is indicative of a basic (alkaline) solution.
Conclusion for pH:
- A basic solution usually has a pH above 7. Based on the observation where the universal indicator paper turned blue, a reasonable suggested pH for the basic solution could be around 8.
So, the pH of solution Y is 8.
### Part (b): Identify solution Y
We'll go through each test and interpret the observations step by step to identify solution Y.
Test 1:
- Universal indicator paper turning blue indicates a basic solution. This means solution Y is not acidic but basic.
Test 2:
- Aqueous copper(II) sulfate added to the solution resulted in the formation of a blue precipitate.
- A blue precipitate with copper(II) sulfate typically indicates the presence of carbonate ions (CO₃²⁻).
- Indicating solution Y has carbonate ions.
Test 3:
- A red flame observed during the flame test.
- A red flame is characteristic of lithium ions (Li⁺).
Test 4:
- Addition of dilute sulfuric acid causing no visible change but slight warming.
- This further confirms the presence of carbonate ions because the reaction between carbonate ions and dilute sulfuric acid produces carbon dioxide (CO₂) and water (H₂O), which might not show visible bubbling but causes slight warming.
Combining all observations:
- Solution Y is a basic solution.
- It contains lithium ions (Li⁺) and carbonate ions (CO₃²⁻).
From these observations, it is reasonable to conclude that solution Y is Lithium Carbonate (Li₂CO₃).
So, the identified solution Y is Lithium Carbonate (Li₂CO₃).
