"If claims 1-4 disclose process for the preparation of a crystalline base of some compound and claims 5-10 disclose process for the preparation of salt by incorpoarting the crysatlline base of the same compound.
In such a case does it lacks unity of invention??"
From whatever information you have given 1-4 created the crystalline base for some compound. 5-10 used crystalline base to prepare a salt[a compound/chemical]. 1-4 are original inventors and 5-10 used the original invention to prepare their salt and so that's no invention. A very rough parallel: Einstein's E=Mc2 was proved by Michelson Morley Experiment. Einstein was the discoverer. Just a thought.
And who did what and when is another aspect which needs to be thrashed out.