Using the following spontaneous reactions, classify the 3 metals involved (Cr, Sn, Al) according to increasing reductant properties.
a) 2Cr + 3Sn2+ ----> 2Cr3+ + 3Sn
b) Al + Cr3+ ----> Al3+ + Cr
To classify the 3 metals (Cr, Sn, Al) according to increasing reductant properties based on the given spontaneous reactions, we need to compare their abilities to be oxidized.
The more easily a metal is oxidized, the stronger the reductant it is. Therefore, the metal that undergoes oxidation in a given reaction is the weaker reductant, while the metal that gets reduced is the stronger reductant.
Let's analyze the two reactions:
a) 2Cr + 3Sn2+ ----> 2Cr3+ + 3Sn
In this reaction, chromium (Cr) is getting oxidized from Cr to Cr3+, and tin (Sn) is getting reduced from Sn2+ to Sn. Therefore, tin (Sn) is the stronger reductant compared to chromium (Cr).
b) Al + Cr3+ ----> Al3+ + Cr
In this reaction, aluminum (Al) is getting oxidized from Al to Al3+, and chromium (Cr) is getting reduced from Cr3+ to Cr. Therefore, aluminum (Al) is the stronger reductant compared to chromium (Cr).
So, based on these reactions:
Increasing reductant properties: Cr < Sn < Al
Therefore, the metals can be classified according to increasing reductant properties as follows:
1. Chromium (Cr)
2. Tin (Sn)
3. Aluminum (Al)
To classify the three metals (Cr, Sn, Al) according to increasing reductant properties, we need to determine which metal is the weakest reducing agent and which metal is the strongest reducing agent.
A reducing agent is a substance that undergoes oxidation (loses electrons) in a redox reaction, thereby reducing another substance. In other words, it donates electrons to another substance.
Let's analyze the two given reactions to determine the reductant properties of the metals involved:
a) 2Cr + 3Sn2+ ----> 2Cr3+ + 3Sn
In this reaction, chromium (Cr) is oxidized from a 0 (+0) oxidation state to a +3 oxidation state. It loses 3 electrons per Cr atom. On the other hand, tin (Sn) is reduced from a +2 oxidation state to a 0 (+0) oxidation state. It gains 2 electrons per Sn atom.
b) Al + Cr3+ ----> Al3+ + Cr
In this reaction, aluminum (Al) is oxidized from a 0 (+0) oxidation state to a +3 oxidation state. It loses 3 electrons per Al atom. Chromium (Cr) is reduced from a +3 oxidation state to a 0 (+0) oxidation state. It gains 3 electrons per Cr atom.
Based on these reactions, we can determine that the metals involved in increasing reductant properties are as follows:
1. Aluminum (Al) - It loses 3 electrons per atom, making it the weakest reducing agent.
2. Chromium (Cr) - It gains 3 electrons per atom, making it a stronger reducing agent than aluminum.
3. Tin (Sn) - It gains 2 electrons per atom, making it the strongest reducing agent among the three metals.
Therefore, the classification of the three metals according to increasing reductant properties would be: Al < Cr < Sn.