The correct options (s) to distinguish nitrate salts of `Mn^(2+)` and `Cu^(2+)` taken separately is (are)

Options

A. `Mn^(2+)` show the characteristic green colour in the flame test
B. only `Cu^(2+)` show the formation of precipitate by passing `H_(2)S` in acidic medium
C. Only `Mn^(2+)` show the formation of precipitate by passing `H_(2)S` in faintly basic medium
D. `Cu^(2+)//Cu` has higher reduction potential than `Mn^(2+)//Mn` (measured under similar conditions)

Answer

B, D

Explanation

only `Cu^(2+)` ions can give a precipitate (black) by passing `H_(2)S` gas in the acidic medium.
`E^(@) Cu^(2)//Cu (+0.34V)` is higher than `E^(@)Mn^(2+)//Mn (-1.18V)` in the electrochemical series.