Question

In a galvanic cell why anode is negative and cathode is positive.

Answer 1

Hint: We need to know that the cation is a positively charged species while anion is a negatively charged species. At the cathode, the reduction reaction which consumes electrons (leaving behind positive (metal) ions at the electrode) and at anode, oxidation takes place in which electrons flow out towards the external part of the circuit.

Complete answer:
An apparatus that is used to generate electricity from a spontaneous redox reaction or, conversely, that uses electricity to drive a non-spontaneous redox reaction is called an electrochemical cell.
A galvanic (voltaic) cell uses the energy released during a spontaneous redox reaction
(\[\Delta G < 0\Delta G < 0\]) to generate electricity.
Let’s consider the reaction of metallic zinc with cupric ions (\[C{u^{2 + }}\]) to give copper metal and \[Z{n^{2 + }}\] ions.
The balanced chemical equation is as follows: \[Zn\left( s \right) + C{u^{2 + }}\left( {aq} \right) \to Z{n^{2 + }}\left( {aq} \right) + Cu\left( s \right)\]
Insert a zinc rod into an aqueous solution of copper (II) sulfate. As the reaction proceeds, the zinc rod dissolves, and a mass of metallic copper forms. Zinc metal is oxidized to \[Z{n^{2 + }}\] ions at the zinc electrode (the anode), and \[C{u^{2 + }}\] ions are reduced to \[Cu\] metal at the copper electrode (the cathode). Anode is negative in an electrochemical cell because it has a negative potential with respect to the solution while anode is positive in an electrolytic cell because it is connected to the positive terminal of the battery.

Note:
We have to know that the galvanic cell utilizes the ability to separate the flow of electrons in the process of oxidation and reduction, causing a half reaction and connecting each with a wire so that a path can be formed for the flow of electrons through such wire. This flow of electrons is essentially called a current.