what is the line botation and overall balanced reaction of Cr, Cr2 ,Co2 ,and Co
The correct answer and explanation is:
Correct Answer:
Half-reactions (line notation):
- Cr → Cr³⁺ + 3e⁻
- Cr₂O₇²⁻ + 14H⁺ + 6e⁻ → 2Cr³⁺ + 7H₂O
- Co²⁺ + 2e⁻ → Co
- Co → Co²⁺ + 2e⁻
Overall Balanced Redox Reaction:
To write the overall redox reaction, we combine the oxidation and reduction half-reactions in a balanced way. Here is a typical redox reaction involving Cr₂O₇²⁻ (oxidizing agent) and Co (reducing agent):
Cr₂O₇²⁻ + 14H⁺ + 6Co → 2Cr³⁺ + 6Co²⁺ + 7H₂O
300-Word Explanation:
This redox reaction involves chromium and cobalt in different oxidation states. Chromium in the dichromate ion (Cr₂O₇²⁻) acts as an oxidizing agent and is reduced to Cr³⁺. Cobalt metal (Co), on the other hand, acts as a reducing agent and is oxidized to Co²⁺.
In acidic solution, dichromate (Cr₂O₇²⁻) accepts electrons and is reduced:
Cr₂O₇²⁻ + 14H⁺ + 6e⁻ → 2Cr³⁺ + 7H₂O
This half-reaction shows chromium going from +6 in Cr₂O₇²⁻ to +3 in Cr³⁺. It consumes hydrogen ions (H⁺) and produces water.
The cobalt metal is oxidized:
Co → Co²⁺ + 2e⁻
To balance the overall reaction, we need equal numbers of electrons in the oxidation and reduction half-reactions. The chromium half-reaction involves 6 electrons, so we need 3 cobalt atoms to provide 6 electrons:
3Co → 3Co²⁺ + 6e⁻
Now combine:
Cr₂O₇²⁻ + 14H⁺ + 3Co → 2Cr³⁺ + 3Co²⁺ + 7H₂O
This balanced equation satisfies both mass and charge conservation. The total charge on both sides is equal: on the left, we have 2⁻ (from Cr₂O₇²⁻) plus 14⁺ (from H⁺) equals 12⁺; on the right, 2Cr³⁺ and 3Co²⁺ also equal 12⁺.
Redox reactions like this are important in electrochemistry and corrosion science. They also have real-world uses in industrial processes and batteries.