Hello! Your answer will be C. If you need an explanation let me know!
Hess' Law can best be described as A. <span>Heat evolved in a given process can be expressed as the sum of the heats of several processes that, when added, yield the process of interest. </span>
Answer : The value of equilibrium constant (Kc) is, 0.0154
Explanation :
The given chemical reaction is:

Initial conc.
0 0
At eqm.
x x
As we are given:
Concentration of
at equilibrium = 
That means,

The expression for equilibrium constant is:
![K_c=\frac{[SO_2][Cl_2]}{[SO_2Cl_2]}](https://tex.z-dn.net/?f=K_c%3D%5Cfrac%7B%5BSO_2%5D%5BCl_2%5D%7D%7B%5BSO_2Cl_2%5D%7D)
Now put all the given values in this expression, we get:



Thus, the value of equilibrium constant (Kc) is, 0.0154
The atomic number is the number of protons in the nucleus