Assertion: F is more electronegative than Cl.Reason: F has higher electron affinity than Cl.(a) If both assertion and reason are true and the reason is a correct explanation of the assertion.(b) If both assertion and reason are true but reason is not a correct explanation of the assertion.(c) If the assertion is true but reason is false.(d) If both the assertion and reason are false.(e) If the assertion is false but the reason is true.

The correct option is:

(c) If the assertion is true but the reason is false.

Explanation:

The assertion that "F is more electronegative than Cl" is true. Fluorine (F) is indeed more electronegative than chlorine (Cl). Electronegativity is a measure of an atom's ability to attract electrons in a chemical bond, and fluorine, being the most electronegative element, attracts electrons more strongly than chlorine.
However, the reason given, "F has higher electron affinity than Cl," is false. Electron affinity is the energy change that occurs when an electron is added to a neutral atom to form a negative ion. While both fluorine and chlorine have high electron affinities due to their high electronegativities, fluorine actually has a lower electron affinity than chlorine. This is because fluorine already has a high electron density and adding an additional electron to it results in significant repulsion due to electron-electron repulsion. Chlorine, on the other hand, has a slightly lower electron density and thus can accept an additional electron more readily than fluorine.
Therefore, while the assertion is true, the reason provided to explain it is false. Thus, option (c) is the correct choice.