Satyadeep, The policy of granting grace marks or what is generally known as the normalization procedure depends entirely on the educational board you are studying in. See, to be honest, it is very difficult to predict whether you would be given grace marks or not as it entirely depends on your educational board and its' normalization norms. Now, if the exams of those two subjects where you think you have not performed well are done, then you cannot change anything and thinking about the marks or the chances of passing would not do any good, rather focus on other subjects so that you can compensate for that "not-so good" performed exams.In addition to it , you should not predict anything until the results are out as you never know the examiner's mindset while checking your answers and you might end up getting more marks than expected , so all you can do is to hope for the best and prepare for the other exams, if there are any.

So, regarding grace marks or what some technically refer to as normalization, it is very difficult to predict if there would be grace marks given, although most of the educational boards and the authorities have a policy of normalization of marks in case of marks being very close to passing marks, so you should hope for the same.

Good Luck for all your exams.