Question

Which of the following reactions takes place during formation of ionic bonds?
(A) Redox reaction
(B) Addition reaction
(C) Substitution reaction
(D) Elimination reaction

Answer 1

Ionic bonds form when the valence (outermost) electrons of one atom are transferred permanently to another atom. The atom that loses the electrons becomes a positively charged ion (cation), while the one that gains them becomes a negatively charged ion (anion).

Complete Step By Step Answer:
Ionic bond is formed by transfer of electrons, during this transfer of electrons one atom donates its electron to form cations and another atom accepts electrons. Since both reduction and oxidation takes place simultaneously this is called redox reaction.
Redox reactions are characterized by the actual or formal transfer of electrons between chemical species, most often with one species undergoing oxidation while another species undergoes reduction. The chemical species from which the electron is removed is said to have been oxidized, while the chemical species to which the electron is added is said to have been reduced. In other words, Oxidation is the loss of electrons or an increase in the oxidation state of an atom, an ion, or of certain atoms in a molecule. Reduction is the gain of electrons or a decrease in the oxidation state of an atom, an ion, or of certain atoms in a molecule.
So, the correct answer is (A) redox reaction.

Note:
Many reactions are redox reactions due to changes in oxidation states but without distinct electron transfer. For example, during the combustion of wood with molecular oxygen, the oxidation state of carbon atoms in the wood increases and that of oxygen atoms decreases as carbon dioxide and water are formed. The oxygen atoms undergo reduction, formally gaining electrons, while the carbon atoms undergo oxidation, losing electrons. Thus oxygen is the oxidizing agent and carbon is the reducing agent in this reaction.