Equilibrium and Catalysis MCQ

167. A catalyst increases the rate of a reaction by

 (a) decreasing internal energy 

(d) decreasing activation energy 

(c) increasing activation energy 

(d) decreasing enthaipy 

161. The free-energy change of reversible reaction at equilibrium state of reaction is

 (a) positive (c) negative 

 (b) zero      (d) infinite 

162. According to the third law of thermodynamics at zero degree kelvin the entropy is zero for 

(a) 2NH3-Nz+3H2 

(b) H2+ Cl22HC 

(c) 203 302 

(d) Ph(C)NCOCH3p-CLCHNHCOCH3

169. When a solid melts, there is 

(a) covalent solids at 25 atm pressure 

(b) elements in their stable form 

(C) perfectly crystalline solids 

(d) any compound in their liquid form.

 163. Which of the following expression is correct for the first order reaction (A, refers to initial concentration)? 

(a) no change in enthalpy 

(b) no change in entropy 

(c) decreasing in enthalpy 

(d) increasing in enthalpy 

170. A process is said to be spontaneous if 

(a) AG is positive (b) AG is negative 

(c) AS is negative (d) AH is negative