Podcast Beta
Questions and Answers
What acts as the anode in the electroplating of zinc?
Chromium ions are deposited at the anode during electroplating.
False
What kind of acid is used in the electroplating process of chromium?
Chromic acid
Zinc ions are discharged at the ______ during electroplating.
Signup and view all the answers
Match the following components of electroplating with their roles:
Signup and view all the answers
Which of the following is an example of an alloy that resists corrosion?
Signup and view all the answers
Paints and coatings do not help in preventing corrosion.
Signup and view all the answers
What is the process of applying a metal coating to protect another metal from corrosion called?
Signup and view all the answers
The rust formed on iron is described as _______ and porous.
Signup and view all the answers
Match the following corrosion prevention methods with their descriptions:
Signup and view all the answers
What is produced at the anode during the electrolysis process in the Nelson cell?
Signup and view all the answers
Hydrogen gas is produced at the cathode during the electrolysis of NaCl solution.
Signup and view all the answers
What material is used to coat the cathode in the Nelson cell?
Signup and view all the answers
The overall reaction during the manufacture of NaOH from brine involves the conversion of 2NaCl(aq) and 2H₂O(l) to 2NaOH(aq), Cl₂(g), and ______(g).
Signup and view all the answers
Match the following components of the Nelson cell with their descriptions:
Signup and view all the answers
What is one of the significant changes in chlorine production methods mentioned?
Signup and view all the answers
What role does the catch basin serve in the Nelson cell?
Signup and view all the answers
The Nelson cell functions by using a U-shaped tube made of glass.
Signup and view all the answers
Study Notes
Manufacturing NaOH from Brine
- The Nelson cell is used to produce NaOH from Brine (concentrated NaCl solution) through electrolysis.
- The cell consists of a U-shaped steel tube, perforated and serving as the cathode, with a graphite anode suspended inside.
- Asbestos lining isolates the cathode from the anode.
- During electrolysis, Chlorine is produced at the anode and collected at the chlorine outlet.
- Hydrogen gas is generated at the cathode and collected at the hydrogen outlet.
- Sodium hydroxide (NaOH) is collected in the catch basin located beneath the U-shaped tube.
Components of Nelson Cell
- Asbestos (made of Calcium and Magnesium)
- Graphite Anode
- Steel Mesh Cathode with porous asbestos lining
- Saturated NaCl solution (Brine)
- NaOH
- Steam
Reactions in Nelson Cell
- Anode Reaction: 2Cl⁻(aq) → Cl₂(g) + 2e⁻
- Cathode Reaction: 2H₂O(l) + 2e⁻ → H₂(g) + 2OH⁻(aq)
- Overall Reaction: 2NaCl(aq) + 2H₂O(l) → 2NaOH(aq) + Cl₂(g) + H₂(g)
Corrosion Prevention Methods
- Alloying: Mixing metals or metals with non-metals to enhance resistance to corrosion (e.g., stainless steel (Iron, Chromium, Nickel)).
- Paints and Coatings: Applying protective layers to prevent corrosion and weathering (modern paints include stabilizers).
- Removal of Stains: Cleaning and removing stains on metal surfaces to prevent further corrosion as these areas act as points for corrosion initiation.
Further Atmospheric Action on Rust
- Rust (Fe(OH)3) formed on iron is porous, allowing further atmospheric action and corrosion.
- Chemical equations:
- $Fe + 3H_2O \rightarrow Fe(OH)3{s} + 3H^+{(aq)}$
- $Fe^{2+} + 2OH^{-} \rightarrow Fe(OH)_2{s}$
Electroplating
-
Electroplating of Zinc:
- Cleaning the zinc object and immersing it in a zinc sulfate ($ZnSO_4$) solution with sulfuric acid ($H_2SO_4$).
- The object being plated acts as the cathode, and a zinc plate/rod acts as the anode.
- Anode Reaction: $Zn(s) \rightarrow Zn^{2+}(aq) + 2e^-$
- Cathode Reaction: $Zn^{2+}(aq) + 2e^- \rightarrow Zn(s)$
- Zinc ions are discharged at the cathode and deposit as zinc metal.
-
Electroplating of Chromium:
- A pure chromium piece ($Cr(s)$) serves as the anode, immersed in chromic acid ($H_2CrO_4$) solution with a small amount of sulfuric acid ($H_2SO_4$).
- The object being plated acts as the cathode.
- Anode Reaction: $Cr(s) \rightarrow Cr^{3+}(aq) + 3e^-$
- Cathode Reaction: $Cr^{3+}(aq) + 3e^- \rightarrow Cr(s)$
- Chromium ions are discharged at the cathode and deposit as chromium metal.
Food Preservatives
- Preservatives like organic acids are used in food products to prevent reactions between food and metal containers (e.g., iron) and prevent corrosion.
- Tin-plated steel cans are preferred over iron containers, as tin plating prevents corrosion and preserves the taste of the food.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the process of manufacturing sodium hydroxide (NaOH) from brine using the Nelson cell. This quiz covers the cell's components, the electrolysis reactions taking place, and the overall chemical process involved in producing NaOH, chlorine, and hydrogen gas.
