Identity of metal from electrolysis

In summary, the identity of the metal ion being electrolysed is likely indium, based on the given information of the current, time, and mass plated out. The molar mass calculation supports this conclusion, with indium having the closest match.
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TT0
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Homework Statement


A solution of a trivalent metal ion is electrolysed by a current of 5.0A for 10 minutes during which time 1.18g of metal was plated out. The identity of the metal is:

A cobalt
B chromium
C indium
D gallium
E bismuth

Relative atomic masses:
1 faraday = 96,486 coulombs.

Homework Equations


current*time=coulombs
coulombs/96486=faraday
1 faraday = 1 mol of electrons

The Attempt at a Solution


5.0*10*60=3000 coulombs
3000/96486=0.031092 mol of electron

Since trivalent metal ion, mol of metal = 0.031092/3 = 0.010364 mols

Trial and error by dividing 1.18 by molar mass shows indium is closest. 1.18/114.82 = 0.1028. Is this the correct answer?

Cheers!
 
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  • #2
Yes, indium sounds good.
 
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  • #3
Thanks!
 
  • #4
To avoid trial and error use this formula:

Molar mass (g/mol)=mass(g)/number of moles(mol)
M=m/n
M= 1.18g/ 0.010364 mol
M=113.86 g/mol

Cd
113.86-112.41=1.45 difference
Indium
114.82-113.86=0.96 difference

So the closest answer is Indium
 

1. What is electrolysis and how does it identify metals?

Electrolysis is a process in which an electric current is used to separate a compound into its individual components. In the case of identifying metals, electrolysis is used to break down a metal compound into its pure form, allowing for analysis of its properties and characteristics.

2. Can electrolysis identify all types of metals?

No, electrolysis can only identify metals that are present in a compound. It cannot identify elements that are not part of a compound, such as pure metals or metal alloys.

3. How accurate is electrolysis in determining the identity of a metal?

Electrolysis is a highly accurate method of identifying metals, as it allows for the isolation and analysis of the pure metal. However, it is important to note that other methods, such as spectroscopy, may also be used in conjunction with electrolysis for a more comprehensive analysis.

4. What are some common applications of electrolysis in identifying metals?

Electrolysis is commonly used in metallurgy and material science for identifying the composition of metals in various alloys and compounds. It is also used in forensic science to analyze trace metals found at crime scenes.

5. Are there any limitations to using electrolysis for identifying metals?

Yes, there are some limitations to using electrolysis for identifying metals. Some metals may not be easily separated through electrolysis, and the process can be time-consuming and expensive. Additionally, electrolysis may not be suitable for identifying certain types of metals, such as radioactive or highly reactive metals.

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