Can mixing a cation and an anion lead to the formation of an insoluble?

Which statement justifies that phosphine (ph3) is a polar molecule?

How have the greenhouse gasses increased from the year 2000 to 2018

Which is a characteristic of the electron sea model for metallic bonding? molecular orbitals overlap to produce bands. electrons flow easily between metal nuclei. electrons are in fixed positions in the orbitals. atomic nuclei are arranged in an irregular pattern.