Arrange the following metals in the order in which they displace each other from the solution of their salts.
Al, Cu, Fe, Mg and Zn
Al, Cu, Fe, Mg and Zn
Solution and Explanation
When comparing the reducing power of different metals, it's important to note that a metal with stronger reducing power can replace a metal with weaker reducing power in a solution containing its salt. In this context, the metals can be arranged in increasing order of reducing power:
Cu < Fe < Zn < Al < Mg.
Consequently, we can conclude that magnesium (Mg) has the ability to displace aluminum (Al) from a solution of its salt. However, aluminum (Al) lacks the capability to displace magnesium (Mg) in a similar manner.
So, the sequence in which these metals can replace each other in the solutions of their respective salts is as follows:
Mg > Al > Zn > Fe > Cu
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Give one chemical test to distinguish between the following pairs of compounds.
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(i) Which of the electrode is negatively charged?
(ii) The carriers of the current in the cell.
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(iii) Sn(s) | Sn2+(0.050 M) || H+ (0.020 M) | H2(g) (1 bar) | Pt(s)
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Concepts Used:
Electrochemical Cells
An electrochemical cell is a device that is used to create electrical energy through the chemical reactions which are involved in it. The electrical energy supplied to electrochemical cells is used to smooth the chemical reactions. In the electrochemical cell, the involved devices have the ability to convert the chemical energy to electrical energy or vice-versa.
Classification of Electrochemical Cell:
Cathode
- Denoted by a positive sign since electrons are consumed here
- A reduction reaction occurs in the cathode of an electrochemical cell
- Electrons move into the cathode
Anode
- Denoted by a negative sign since electrons are liberated here
- An oxidation reaction occurs here
- Electrons move out of the anode
Types of Electrochemical Cells:
Galvanic cells (also known as Voltaic cells)
- Chemical energy is transformed into electrical energy.
- The redox reactions are spontaneous in nature.
- The anode is negatively charged and the cathode is positively charged.
- The electrons originate from the species that undergo oxidation.
Electrolytic cells
- Electrical energy is transformed into chemical energy.
- The redox reactions are non-spontaneous.
- These cells are positively charged anode and negatively charged cathode.
- Electrons originate from an external source.