What minimum concentration of k2co3 is required to cause the precipitation of the cation that precipitates first?

The concentration is ion dependent

Explanation:

The concentration is dependent on the amount of the ions in the solution. This is the rate-determination factor. For a reaction to precipitate, there should be enough ions in the solution.  In addition, the Ksp plays an important factor in the reaction. This happens when the amount of ions formed is derived from a strong ionic solution. This then drives the reaction forward.

Ultraviolet Light

Explanation:

The energy of a photon that will be released if an electron falls from the n= 2 orbit (excited state) to the n0 = 1 orbit (ground state) is of ultraviolet light. In the ultraviolet part of the spectrum, a photon having an energy of 10.2 eV has a wavelength of 1.21 x 10-7 m.Hence, when an electron wants to jump or it gets excited from the first level to the second level that is from n = 1 orbit to n = 2 orbits, it must absorb a photon of ultraviolet light. But,When an electron falls from n = 2 orbit to n = 1 orbit  or from n = 2 orbit(excited state) to n = 0 orbit(groubd state), it emits a photon of ultraviolet light.