Let's analyze each reaction step by step, determining the oxidation numbers for each element, identifying what was oxidized/reduced, and classifying the type of reaction.
Reaction 1: Zn + 2HCl → ZnCl2 + H2
Oxidation Numbers:
- Zn: 0 (as a pure element)
- H in HCl: +1
- Cl in HCl: -1
- Zn in ZnCl2: +2
- Cl in ZnCl2: -1
- H in H2: 0 (as a pure element)
Identifying Oxidation and Reduction:
- Oxidized: Zn (goes from 0 to +2)
- Reduced: H+ (in HCl goes from +1 to 0)
Type of Reaction: This is a single displacement reaction (or single replacement reaction).
Reaction 2: Cu + 2 AgNO3 → 2 Ag + Cu(NO3)2
Oxidation Numbers:
- Cu: 0 (as a pure element)
- Ag in AgNO3: +1
- N in NO3: +5
- O in NO3: -2
- Cu in Cu(NO3)2: +2
- Ag: 0 (as a pure element)
Identifying Oxidation and Reduction:
- Oxidized: Cu (goes from 0 to +2)
- Reduced: Ag+ (goes from +1 to 0)
Type of Reaction: This is also a single displacement reaction (or single replacement reaction).
Reaction 3: 2 Na + Cl2 → 2 NaCl
Oxidation Numbers:
- Na: 0 (as a pure element)
- Cl in Cl2: 0 (as a pure element)
- Na in NaCl: +1
- Cl in NaCl: -1
Identifying Oxidation and Reduction:
- Oxidized: Na (goes from 0 to +1)
- Reduced: Cl (goes from 0 to -1)
Type of Reaction: This is a combination reaction (also known as a synthesis reaction).
Summary
-
Zn + 2HCl → ZnCl2 + H2
- Oxidized: Zn
- Reduced: H+
- Type of Reaction: Single displacement
-
Cu + 2 AgNO3 → 2 Ag + Cu(NO3)2
- Oxidized: Cu
- Reduced: Ag+
- Type of Reaction: Single displacement
-
2 Na + Cl2 → 2 NaCl
- Oxidized: Na
- Reduced: Cl
- Type of Reaction: Combination (synthesis)