Question

Name one common reagent that can precipitate or react and differentate following pairs:
a. `Ag^(Theta)` and `B^(2+)` b. `Cu^(2+) , Pb^(2+)`
c. `I^(Theta)` and `CI^(Theta)` d. `I^(Theta)` and `Br^(Theta)`
e. `SO_(3)^(2-)` and `SO_(4)^(2-)` i. `Fe^(3+) , Cu^(2+)`
g. `Co^(2+)` and `Cu^(2+)`

Answer 1

a. `K_(2)Cr_(2)O_(4)`
`2Ag^(o+) + CrO_(4)^(2+) rarr underset(Red)(Ag_(2))CrO_(4)darr`
`Ba^(2+) + CrO_(4)^(2+) rarr underset("Yellow")(BaCrO_(4)darr)`
b. `K_(2) CrO`
`Cu^(2+) + CrO_(4)^(2-) rarr underset("Chocolate")(CuCrOdarr)`
`Pb^(2+) + CrO_(4)^(2+) rarr underset("Yellow")(PbCrO_(4)darr)`
c. `AgNO_(3)`
`Ag^(o+) + I^(Theta) rarr underset("Yellow")(AgI darr) Ag^(o+) + CI^(Theta) rarr underset("White")(AgCI darr)`
d. `CI_(2)` water `+ CHCI_(3)`
`21^(Theta) +CI_(2) rarr underset(CHCI_(3)"layer")underset(("Violet in"))I_(2)+2CI^(Theta) 2Br^(Theta) +CI_(2) rarr underset(CHCI_(3)layer)underset("Orange in")(Br_(2) +2CI^(Theta))`
e.`BaCI_(2)`
`BaCI_(2) +SO_(3)^(2-) rarr underset("White ppt. soluble in conc"HCI)(BaSO_(3)darr)`
`BaCI_(2) +SO_(4)^(2-) rarr underset("White ppt. insoluble in conc"HCI)(BaSO_(4)darr)`
f. `NH_(4)SCN`:
`Fe^(3+) +SCN^(Theta) rarr underset("Red colour")([Fe(SCN)]^(2+))`
`Cu^(2+) +2SCN^(Theta) rarr underset(Black)(Cu(SCN)_(2)darr)`
g. `NH_(4)SCN`:
`Co^(2+) +4SCN^(Theta) rarr underset("Blue colour")([Co(SCN)_(4)]^(2-))`
`Cu^(2+) +2SCN^(Theta) rarr underset(Black)(Cu(SCN)_(2)darr)`