The term that refers to compounds that can form hydrates but do not contain water molecules is anhydrous.
Answer : The temperature in kelvins is, 
Explanation : Given,
= 178.5 KJ/mole = 178500 J/mole
= 161.0 J/mole.K
Gibbs–Helmholtz equation is :

As per question the reaction is spontaneous that means the value of
is negative or we can say that the value of
is less than zero.

The above expression will be:



Now put all the given values in this expression, we get :


Therefore, the temperature in kelvins is, 
A radioactive element has an unstable nucleus that emits particles in the form of alpha, beta, or gamma radiation. A stable element has a nucleus that does not emit such particles