Why does the colour of copper sulphate solution change when
an iron nall Is dipped in it?​

when an iron nail immersed in the solution of copper sulphate than iron displaces copper from the solution of copper sulphate because iron is more reactive than copper. Therefore copper sulphate solution colour changes from blue to pale green.

the word that best sums up the tone of the newspaper regarding the treaty of versailles is resentful.