The reaction between nitrogen and hydrogen to form ammonia is exothermic The strengths of the bonds in the three molecules are as shown. Which statement can be deduced from this information?

Answer:

15) D

Number of N ≡ N bonds in reactants = 1
Total energy of N ≡ N bonds in reactants = 1 * x = x
Number of H – H bonds in reactants = 3
Total energy of H – H bonds in reactants = 3 x y = 3y

Number of N – H bonds in products = 3 x 2 = 6
Total energy of N – H bonds in products = 6 x z = 6z

Since the reaction is exothermic, Energy of products must be greater than energy of reactants. 

Therefore, we get the inequality:

6z > x + 3y