Questions

It's a logic question. The answer can be

Boy can propose because he is not blind,deaf n dumb. It was not mentioned that the girl have to understand his proposal.

Jean-Jacques Rousseau (1712–1778), in his influential 1762 treatise The Social Contract, outlined a different version of social contract theory, as the foundations of political rights based on unlimited popular sovereignty.

Silver nitrate is the basic substance from which silver bromide is obtained. The photographic films are impregnated with the light sensitive AgBr.

The stability of the ions is determined by the energy of the lone pairs. Carbon has the least effective nuclear charge (Zeff) and so the lone pair on the CH3− ion has the highest energy, making it the least stable ion and so the strongest base. The Zeff increases as we move across the period until we get to fluorine which has the greatest Zeff and so its lone pairs have the lowest energy, making F− the least basic ion.

In order of decreasing basicity they are ranked LiCH3 > LiNH2 > LiOH > LiF. We are dealing with the ions F−, OH−, NH2− and CH3− and so the factor which influences their basicity is the stability of the ion compared to its conjugate acid.