JEE MAIN - Chemistry (2018 - 16th April Morning Slot - No. 22)
The incorrect statement is :
Cu2+ salts give red coloured borax bead test in reducing flame.
Cu2+ and Ni2+ ions give black precipitate with H2S in presence of HCl solution.
Ferric ion gives blood red color with potasium thiocyanate.
Cu2+ ion gives chocolate coloured preciitate with potassium ferrocyanide solution.
Explanation
Cu2+ and Ni2+ ions belong to Group II and Group IV respectively.
_16th_April_Morning_Slot_en_22_1.png)
Group II sulphides precipitated out even under low concentration of sulphides, while Group IV sulphides require higher concentration of sulphides. To fulfill this reaction condition, dil. HCl is chosen in Group II reagents and NH4OH is chosen in Group IV reagents.
Comments (0)
