Hmm. lets see
Takfir is to be made, in most cases, by a Qadi and not a lay person or even a mufti as noted by Khalil. The reason for this is because, in the classical age, this implied a loss of rights. Secondly, a lay person accusing another of kufur falls under qathf, a major sin.
"O you who believe! Let not a folk deride a folk who may be better than they (are), not let women (deride) women who may be better than they are; neither defame one another, nor insult one another by nicknames. Bad is the name of lewdness after faith. And whoso turneth not in repentance, such are evil-doers."
from Quran I think.
Abu Zarr reported that the Holy Prophet said: No man accuses another man of being a sinner, or of being a kafir, but it reflects back on him if the other is not as he called him.'' (Bukhari, Book of Ethics; Book 78, ch. 44)
Explain what did congress do which led Jinnah for demanding a separate state ?