Which the following reaction will get affected by increasing the pressure? Also, mention whether change will cause the reaction to go into forward or backward direction.
(i) `COCl_(2) (g) hArr CO(g) + Cl_(2)(g)`
(ii) `CH_(4)(g) + 2S_(2)(g) hArr CS_(2)(g) + 2H_(2)S(g)`
(iii) `CO_(2)(g) + C(s) hArr 2CO(g)`
(iv) `2H_(2)(g) + CO(g) hArr CH_(3)OH(g)`
(v) `CaCO_(3)(s) hArr CaO(s) + CO_(2)(g)`
(vi) `4NH_(3)(g) + 5O_(2)(g) hArr 4NO(g) + 6H_(2)O(g)`

Explanation

Reaction affected will be those in which `(n_(p) ne N_(r))_("gaseous")`. Hence, reaction (a), (b), (c ), (d) and (e) will be affected. By applying Le Chatelier's principle, we can predict the direction.
a. `n_(p)=2, n_(r)=1, i.e., n_(p)gt n_(r)`, reaction will go in the backward direction
b. `n_(p)=3, n_(r)=3, i.e., n_(p)= n_(r)`, reaction will not be affected by pressure
c. `n_(p)=2, n_(r)=1, i.e., n_(p)gt n_(r)`, reaction will go in the backward direction
d. `n_(p)=1, n_(r)=3, i.e., n_(p)lt n_(r)`, reaction will go in the forward direction
e. `n_(p)=1, n_(r)=0, i.e., n_(p)gt n_(r)`, reaction will go in the backward direction
f. `n_(p)=10, n_(r)=9, i.e., n_(p)gt n_(r)`, reaction will go in the backward direction