When 2.2 mol each of H2(g) and 12(g) are reacted in a 1.00 L container at a certain temperature. After the reaction comes to equilibrium, you observe 3.7 mol of HI is present. Calculate the value of the 
 
A. Equilibrium constant (K_c) 
B. Initial concentration of HI 
C. Change in concentration of H2 
D. Equilibrium partial pressure of H2