Answer:
Predominantly ,the color is due to cation Ba2+.
Explanation:
Flame Test : The flame due barium cation is Green in color.
Anions such as Cl- and SO42- slightly (very little) affects the color . Hence ,
BaCl2 and BaSO4 gives Yellow -green flame not pure green
Ba 2+ cation gives green colour because:
It has loosely bounded outermost electron (low ionisation)
It absorb energy from the flame , get excited to higher energy state. When the excited electron comes back to ground state , it emits colour of particular frequency.
