According to Second law the engine based on the cyclic
process is not possible in which we can convert all the heat
into the work. There are a number of statements for the
second law but the two most common statements are.
Kelvin plank statement
process is possible whose sole result is the absorption of
heat from a reservoir and the conversion of all of this heat
No process is possible whose sole result is the transfer of
heat from a colder to a hotter body.