Oxidation and Reduction

Aim:

To see which metals react with dilute hydrochloric acid and also other metal’s nitrate solutions.

Equipment:

Refer to Exploring Chemistry page 164

Procedure:

Refer to Exploring Chemistry page 165

Results:

Reactants	Observation	Products
Magnesium + Hydrochloric Acid	Magnesium dissolved a little while making a fizzing sound. On pop test it popped	Magnesium Chloride + Hydrogen
Zinc + Hydrochloric Acid	Bubbled a little however on the pop test, the flame only became brighter but did not pop	Zinc Chloride + Hydrogen
Lead + Hydrochloric Acid	Created 2-3 bubbles during experiment and could not get pop on pop test	Lead Chloride + Hydrogen
Copper + Hydrochloric Acid	Nothing happened	Copper + Hydrochloric Acid

Reactants	Magnesium Nitrate	Zinc Nitrate	Lead Nitrate	Copper Nitrate
Magnesium	NVR*	Magnesium strip becomes black	Magnesium strip becomes darker while making a dark flack on itself	Magnesium strip becomes black
Zinc	NVR*	NVR*	Zinc Strip becomes black	Zinc Strip becomes black
Lead	NVR*	NVR*	NVR*	N/A
Copper	NVR*	NVR*	NVR*	NVR*

*NVR:  No Visible Reaction

Discussion:

Redox Reactions:

1.      Mg + HCl  -> MgCl + H₂
Mg + 2H⁺ -> Mg²⁺ + H­­_2­
Mg -> Mg²⁺ + 2e^-
2H⁺ + 2e^- -> H₂
Mg + 2H⁺ -> Mg²⁺ + H_2
­Oxidising Agent: H⁺                         Reducing Agent: Mg

2.      Zn + HCl -> ZnCl + H₂
Zn + 2H⁺ -> Zn²⁺ + H­­_2­
Zn -> Zn²⁺ + 2e^-
2H⁺ + 2e^- -> H₂
Zn + 2H⁺ -> Zn²⁺ + H_2
­Oxidising Agent: H⁺                         Reducing Agent: Zn

3.      Pb + HCl -> PbCl + H₂
Pb + 2H⁺ -> Pb²⁺ + H­­_2­
Pb -> Pb²⁺ + 2e^-
2H⁺ + 2e^- -> H₂
Pb + 2H⁺ -> Pb²⁺ + H_2
­Oxidising Agent: H⁺                         Reducing Agent: Pb

4.      Mg + Zn(NO₃)₂ -> Mg(NO₃)₂ + Zn
Mg + Zn²⁺ -> Mg²⁺ + Zn
Mg -> Mg²⁺ + 2e^-
Zn²⁺ + 2e^- -> Zn
Mg + Zn²⁺ -> Mg²⁺ + Zn
_­Oxidising Agent: Zn                         Reducing Agent: Mg

5.      Mg + Pb(NO₃)₂ -> Mg(NO₃)₂ + Pb
Mg + Pb²⁺ -> Mg²⁺ + Pb
Mg -> Mg²⁺ + 2e^-
Pb²⁺ + 2e^- -> Pb
Mg + Pb²⁺ -> Mg²⁺ + Pb
_­Oxidising Agent: Pb                         Reducing Agent: Mg

6.      Mg + Cu(NO₃)₂ -> Mg(NO₃)₂ + Cu
Mg + Cu²⁺ -> Mg²⁺ + Cu
Mg -> Mg²⁺ + 2e^-
Cu²⁺ + 2e^- -> Cu
Mg + Cu²⁺ -> Mg²⁺ + Cu
_­Oxidising Agent: Cu                         Reducing Agent: Mg

7.      Zn + Pb(NO₃)₂ -> Zn(NO₃)₂ + Pb
Zn + Pb²⁺ -> Zn²⁺ + Pb
Zn -> Zn²⁺ + 2e^-
Pb²⁺ + 2e^- -> Pb
Zn + Pb²⁺ -> Zn²⁺ + Pb
_­Oxidising Agent: Pb                         Reducing Agent: Zn

8.      Zn + Cu(NO₃)₂ -> Zn(NO₃)₂ + Cu
Zn + Cu²⁺ -> Zn²⁺ + Cu
Zn -> Zn²⁺ + 2e^-
Cu²⁺ + 2e^- -> Cu
Zn + Cu²⁺ -> Zn²⁺ + Cu
_­Oxidising Agent: Cu                         Reducing Agent: Zn

9.      Pb + Cu(NO₃)₂ -> Pb(NO₃)₂ + Cu
Pb + Cu²⁺ -> Pb²⁺ + Cu
Pb -> Pb²⁺ + 2e^-
Cu²⁺ + 2e^- -> Cu
Pb + Cu²⁺ -> Pb²⁺ + Cu
_­Oxidising Agent: Cu                         Reducing Agent: Pb

Metal Reducing Strength (descending):

1.       Magnesium

2.       Zinc

3.       Lead

4.       Copper

From our experiment we can see multiple things from the results table. First off, we can see the reducing strength of each of the metals experimented on and their reactivity with dilute acids. We can say that Copper is the least reactive out of the metals as it does not react with the dilute hydrochloric acid. It’s also has the weakest reducing strength. We know this by the second results table. It shows us that it does not react with any other metal nitrates. Magnesium on the other hand can definitely be considered as the most reactive and strongest reducing strength. We know this because it extremely reacted with the dilute hydrochloric acid. It also reacted with all three other metal nitrates. From this we can say that copper is the least reactive and has the weakest reducing strength while magnesium has the strongest reducing strength and is the most reactive with dilute acids. From our workbook Chemistry for WA and the results from above, we can say that zinc has the second strongest reducing strength and reactivity with dilute acids. Lead comes in third out of fourth.