Reversibility and Carnot cycle

[LTP]

I have two short questions:

1) Is the Carnot cycle completely reversible?

2) \Delta S = 0 for a reversible process, right?

 

[vivesdn]

Yes, the Carnot cycle is designed as being reversible.

Yes, it is the Clausius theorem for a reversible cycle. On a particular reversible process, a system can increase o decrease its entropy provided that the surroundings decrease or increase it by the same amount, as the universe entropy will remain constant.