I think cabsy83 is right. A quiet word with this student at the end of a class may be the answer. Interruptions from students like this often come from frustration and/or insecurity at not understanding, or falling behind the rest of the class. This may be the case. You may find that he is willing to tell you exactly what the problem is if you speak to him alone.
If it is just that he is struggling to keep up, then a solution could be to offer to spend 10 minutes with him after the class sometimes (discreetly - he may not want the others in the class to see that he needs extra help).
I once taught a TOEIC preparation class, in which two girls had a significantly higher level than everyone else. They started to complain that it was too easy and disrupted the class in any way they could! So I talked to them after one class, we discussed the problem and possible solutions, and as soon as they realised that I was just as concerned about their learning as I was about the other students, they became a lot more reasonable and participated normally in the class.
I hope this helps.