Let's analyze the reactions involving ionic salt solutions one by one, based on the provided data:
### Reaction 1: [tex]\( NaOH (aq) + Ni(NO_3)_2 (aq) \)[/tex]
#### Observations after mixing:
- No observable change
- Bubbles formed in mixture
- Mixture's color changed
- Solid formed in mixture
- Test tube felt colder
- Test tube felt hotter
For this reaction, all of the following observations are noted:
1. No observable change: This indicates that sometimes the reaction mixture might not visibly show any sign of reaction.
2. Bubbles formed in mixture: This suggests that a gas could be evolved during the reaction.
3. Mixture's color changed: This implies a chemical change leading to an alteration in the mixture's color.
4. Solid formed in mixture: This indicates that a precipitate (solid) is formed during the reaction.
5. Test tube felt colder: This suggests that the reaction might be endothermic (heat is absorbed).
6. Test tube felt hotter: This suggests that the reaction might be exothermic (heat is released).
### Reaction 2: Unknown Reaction 1
#### Observations after mixing:
- No observable change
- Bubbles formed in mixture
- Mixture's color changed
- Solid formed in mixture
- Test tube felt colder
For this reaction, the following observations are recorded:
1. No observable change: Similar to reaction 1, there might be no visible changes at times.
2. Bubbles formed in mixture: There could be a gas produced during the reaction.
3. Mixture's color changed: Indicates a chemical change with alteration in color.
4. Solid formed in mixture: Formation of precipitate occurs.
5. Test tube felt colder: The reaction might be endothermic (absorption of heat).
Notably, the observation "Test tube felt hotter" is not recorded for the Unknown Reaction 1, implying that this reaction does not show any exothermic behavior.
### Step-by-Step Explanation:
1. For [tex]\( NaOH (aq) + Ni(NO_3)_2 (aq) \)[/tex]:
- The reaction can show various signs such as bubbling, color change, precipitate formation, temperature change (either colder or hotter).
- This implies the reaction is versatile and can exhibit all the listed observations.
2. For the Unknown Reaction 1:
- The observations are generally similar to the first reaction, but there is no observation of the test tube feeling hotter.
- This likely indicates that the reaction is not exothermic, only endothermic or neutral in terms of thermal change.
From the results, we can clearly distinguish that [tex]\( NaOH (aq) + Ni(NO_3)_2 (aq) \)[/tex] has a broader range of observable changes compared to the Unknown Reaction 1.
