In science it is best to continue research, and rinse and repeat. This allows for a stronger hypothesis if you're results are the same every time, or change your hypothesis if you stumble upon new results. <span />
The percent yield of the reaction : 89.14%
<h3>Further explanation</h3>
Reaction of Ammonia and Oxygen in a lab :
<em>4 NH₃ (g) + 5 O₂ (g) ⇒ 4 NO(g)+ 6 H₂O(g)</em>
mass NH₃ = 80 g
mol NH₃ (MW=17 g/mol):

mass O₂ = 120 g
mol O₂(MW=32 g/mol) :

Mol ratio of reactants(to find limiting reatants) :

mol of H₂O based on O₂ as limiting reactants :
mol H₂O :

mass H₂O :
4.5 x 18 g/mol = 81 g
The percent yield :

Answer:
B) They will react because X and Y can share two pairs of electrons to become stable
Explanation:
The electron configurations of two elements x and y are given :
X: 1s2 2s2 2p6
Y: 1s2 2s2 2p6 3s2 3p6
The statement that is true for both the elements is that, they both will react as they both can share two pairs of electrons to become stable.
To become stable the outermost shell or p orbital should have 8 electrons, so element X can gain 2 atoms to become stable.
Element Y can also react as it can also share two atoms to fulfill its 3p orbital and will stable.
Hence, the correct option is "B".