Answer:
The ion present in the sample solution is Mn2+
Explanation:
(a) No precipitate formed when an aqueous solution of NaCl was added to the sample solution.
Most chlorides are quite soluble in water except for he  H g 2 C l 2, that  is an insoluble salt. Since no precipitation formed upon addition of NaCl,  H g 2 +  was not present in the sample.
(b) No precipitate formed when an aqueous solution of Na2SO4 was added to the sample solution.
The  B a S O 4  is an insoluble salt too. Since no precipitation formed upon addition of N a 2 S O 4 ,  the ion B a 2 +  was not present in the sample.
(c) A precipitate formed when the sample solution was made basic with NaOH.
As the M n ( O H ) 2 is insoluble in this last solution, the precipitate formed corresponds to B a S O 4 and H g 2 C l 2 compounds , therefore it can be concluded that the present ion in the sample solution is Mn+2.
