<u>Answer:</u> The correct answer is Option 4: U
<u>Explanation:</u>
Activation energy is defined as the energy that is given to a chemical system with potential reactants to produce products. It is represented as 
It is represented as the energy from the reactants to the activated complex.
Reverse reaction is defined as the reaction in which the products formed become reactants and leads to the formation of reactants back.
So, here, the activation energy of the reverse reaction is the energy between the products and the activated complex, which is represented as letter U in the given graph.
Hence, the correct answer is Option 4: U
Molecular Mass of Compound.






- Molecular mass of O in compound=16(4)=64u




Answer:
Cl
Explanation:
n for Mg=m:Mm
=65.8:24
=2.74mol
n for Cl=m:Mm
=45.7:70
=0.65mol
According to the <em>number of moles</em> we can say that the limiting reagent is Cl as it has few moles.