the acid dissociation constant of ligands derived from s-alkyl dithiocarbazate and stability constants of their complexes with ni(ii), cu(ii) and zn(ii) metal ions in 75% ethanol-water

In this work, the dissociation constants of s-benzyldithiocarbazate (sbdtc)=l1 and s-benzyldithiocarbazate acetophenone (sbdtcac)=l2 and the formation constants of their binary complexes with ni(ii), cu (ii) and zn (ii) were determined by potentiometric titration against 0.1 m koh at 0.1 m kno3 ionic strength in 75% (vv) ethanol-water. all these metal ions form 1:1 and 1:2 binary complexes. the thermodynamic parameters such as δg, δh, and δs of the binary complexes were determined using the vant-hoff equation. conductometric technique was also used to get a complete picture on formation and behaviour of the chelates in solution.