The rate of reaction of which of the following is not affected by pressure?

What are the requirements for chemical synthesis,and how do changes in conditions affect equilibrium and the laws governing it?

Based on Le Chatelier's principle,which of the following information is obtained?

Formation of $SO_3$ takes place according to the reaction:
$2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g); \,\, \Delta H = -45.2 \, kcal$
Which of the following factors favours the formation of $SO_3$?

The reaction $2SO_2 + O_2 \rightleftharpoons 2SO_3$; $\Delta H = -ve$ is favoured by

In a vessel containing $SO_3$,$SO_2$,and $O_2$ at equilibrium,some helium gas is introduced so that the total pressure increases while temperature and volume remain constant. According to Le Chatelier's principle,the dissociation of $SO_3$: