Chemistry

Problem

Sulphide ions in alkaline solution react with solid sulphur to form polyvalent sulphide ions. The equilibrium constant for the formation of

S_2^{2-}

and

S_3^{2-}

from S and

S^{2-}

ions are 1.7 and 5.3 respectively. Calculate equilibrium constant for the formation of

S_3^{2-}

from

S_2^{2-}

and S.