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Need help with multiple choice question (HSC) (1 Viewer)
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tashe
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Okay, really rusty. Hopefully someone can confirm my working out is correct.
http://www.boardofstudies.nsw.edu.au/hsc_exams/hsc2004exams/pdf_doc/chemistry_04.pdf
There are two things you need to know:
That means if an element is the anode (negative terminal) in a galvanic cell, it is being oxidised. (Rewording the 2 points)
The question states "order of increasing ease of oxidation", hence it's Cathode, Anode. Not sure if you understand what I did. Basically, we know that in a galvanic, there's a cathode and anode. Anode is being oxidised so in the order of increasing ease of oxidation, it is Cathode, Anode.
Going back to the question (in the order of increasing ease of oxidation),
Row 1 is: x, Pb
Row 2 is: Pb, y
Row 3 is: Pb, z
From that, we can conclude it's
x, Pb, ... (we need to work out if y or z is easier to oxidise)
---------------------------------------------------------------------------
Looking at Row 2 and Row 3, both has a controlled variable (Pb as the cathode).
The potential difference between Pb and Z is higher than Pb and Y. This means that the reaction between Pb and Z is more spontaneous and that Z is more easier to oxidise.
Hence, x, Pb, y, z.
Answer is D.
Hopefully that explains it. Post any confusion you have about my explanation.
http://www.boardofstudies.nsw.edu.au/hsc_exams/hsc2004exams/pdf_doc/chemistry_04.pdf
There are two things you need to know:
- Anode is the negative terminal in a galvanic cell
- AnOx - Oxidation occurs at the anode
That means if an element is the anode (negative terminal) in a galvanic cell, it is being oxidised. (Rewording the 2 points)
The question states "order of increasing ease of oxidation", hence it's Cathode, Anode. Not sure if you understand what I did. Basically, we know that in a galvanic, there's a cathode and anode. Anode is being oxidised so in the order of increasing ease of oxidation, it is Cathode, Anode.
Going back to the question (in the order of increasing ease of oxidation),
Row 1 is: x, Pb
Row 2 is: Pb, y
Row 3 is: Pb, z
From that, we can conclude it's
x, Pb, ... (we need to work out if y or z is easier to oxidise)
---------------------------------------------------------------------------
Looking at Row 2 and Row 3, both has a controlled variable (Pb as the cathode).
The potential difference between Pb and Z is higher than Pb and Y. This means that the reaction between Pb and Z is more spontaneous and that Z is more easier to oxidise.
Hence, x, Pb, y, z.
Answer is D.
Hopefully that explains it. Post any confusion you have about my explanation.
Thanks once again!