6. CaCl2(s)+2H2O(g)⇌ CaCl2 •2H2O(s)
 Consider the reaction:
The equilibrium constant for the reaction as written is              .
(A) K=[CaCl2·2H2]/([CaCl2][H2O]2)
(B) K=1/[H2O]2
(C) K=1/2[H2O]
(D) K=[H2O]2
(E) K=[CaCl2·2H2O]/[H2O]2