Which of the following is strongest Lewis base?

Explanation

The strongest Lewis base is the one that can donate electrons most effectively. Among the given options, Ethyne is the strongest Lewis base because the carbon atoms in ethyne are sp-hybridized, making the electrons in the triple bond more available for donation. Ethene and Benzene do not have the same electron density available for donation. Ethene is less electron-rich due to sp2 hybridization, and benzene's aromaticity stabilizes its electron cloud, making it less likely to donate electrons. Hence, ethyne is the strongest Lewis base among the options.