For the reaction: I2(g)+Br2(g)⇌2IBr(g)
Kc = 280 at 150 ∘C. Suppose that 0.480 mol IBr in a 2.00-L flask is allowed to reach equilibrium at 150 ∘C.

a) What is the equilibrium concentration of IBr?
b) What is the equilibrium concentration of I2?
c) What is the equilibrium concentration of Br2?

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.