The metal that produces red violet colour in the non-luminous flame is

Step-by-step solution

Alkali metals and their salts impart a characteristic colour to flame. The reason for flame colouration is that the energy of the flame causes an excitation of the outermost electrons which on return to their original position give out the energy so absorbed in the visible region. So Rb gives a red-violet colour to the flame. Zn, Ag, Pb don’t show flame test as they have higher ionization energy so flame test is not possible.