Ethyl acetate, is formed by the reaction of ethanol and acetic acid and equilibrium is represented as

(i) Write the concentration ratio (reaction quotient), Q_c, for this reaction (note:water is not in excess and is not a solvent in this reaction).
(ii) At 293K, if one starts with 1·00 mol of acetic acid and 0·18 mol of ethanol, there is 0·171 mol of ethyl acetate in the final equilibrium mixture. Calculate the equilibrium constant.
(iii) Starting with 0·5 mole of ethanol and 1·0 mole of acetic acid and maintaining it at 293K, 0·214 mole of ethyl acetate is formed after sometime. Has equilibrium been reached ?

(ii) The various molar concentrations before the chemical reaction and at equilibrium point may be represented as
                
Initialconc.          
1 mole          0.180 ml         0                         0
Equilibrium conc.          
1 - 0.171    0.180 - 0.171  = 0.171         0.171 
 (0.829)         (0.009)      = 0.171         0.171
Applying the law of chemical equilibrium,
       
(iii) The various molar concentrations before the reaction and at equilibrium point may be represented as
                       
Initial conc.        
1.00 mole           0.5 mole     0                       0
Equilibrium conc.         
1 - 0.214        0.5- 0.214    =   0.214          0.214
                  
(0.786)            (0.286)      =   0.214          0.214
Concentration ratio,
               
As the value of Q_c is less than the value of equilibrium constant, therefore, the equilibrium has not reached.