Which of the following salts does not form any precipitate with excess of NaOH?
ZnCl2
The given equations are self explanatory
ZnCl2 + NaOH → Zn(OH)2 Na2ZnO2(soluble)
FeCl3 + NaOH → Fe(OH)3 (brown ppt)
CrCl3 + NaOH → Cr(OH)3 (green ppt)
CuSO4 + NaOH → Cu(OH)2 (blue ppt)