Which half reaction can occur at the anode in a voltaic cell

Oxidation is the half reaction that can occur at the anode in a voltaic cell.

Explanation:

In electrodes which is metal strip in voltaic cell the reactions occurs. The two electrodes placed one in each half-cell. The reduction reaction occurs at cathode and oxidation occurs at anode.

A half reaction is either the oxidation or reduction reaction component of a redox reaction. A half reaction is obtained by considering the change in oxidation states of individual substances involved in the redox reaction. Half-reactions are often used as a method of balancing redox reactions.

In an oxidation half reaction, an atom loses electron(s). When an element is oxidized it loses a specific number of electrons.

the millers tale is the answer.

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.