A chemist investigates three unknown solutions, X, Y, and Z, to determine whether they are acidic or alkaline.
- Test 1: They add 20 cm320\text{ cm}^320 cm3 of dilute sodium hydroxide solution to 20 cm320\text{ cm}^320 cm3 of each of the three solutions, then evaporate the liquid to see if a salt remains.
- Test 2: They add a small piece of zinc metal to 20 cm320\text{ cm}^320 cm3 of each of the three solutions.
The chemist's observations are recorded in the table below:
| Solution | Observation after Test 1 | Observation after Test 2 |
|---|---|---|
| X | No salt formed | No change |
| Y | Salt formed | Rapid bubbling |
| Z | Salt formed | Slow bubbling |
a.[4]
Use the observations from both Test 1 and Test 2 to state which solutions are acids and which are alkalis. Explain your answer, comparing the properties of the solutions.
b.[3]
The diagram below shows three titration curves for different acid-alkali combinations where acid is slowly added to an alkali:
Identify which of the curves (D, E, or F) corresponds to each of the following descriptions:
- Strong acid added to weak alkali.
- Weak acid added to strong alkali.
- Strong acid added to strong alkali.
c.[1]
Write the ionic symbol equation, including state symbols, for a neutralisation reaction.