Question

guys pls tell me this how ans came (delta ng)
guys can any1 explain me how delta (ng) came

Answer 1

for seeing ∆n (g) we need to subtract the gaseous moles of reactants from gaseous moles of products . so, moles of product are 2 and moles of reactants are 4 therefore ∆n(g)=2-4=-2

Answer 2

sum of stoichiometry co-efficient of product ---(minus) sum of stoichiometry co efficient of reactant