Answer is: both reactions are exothermic.
<span>In exothermic reactions, heat is released and enthalpy of reaction is less than zero (as it show second chemical reaction).
According to Le Chatelier's principle when the reaction
is <span>exothermic heat is included as a
product (as it show first chemical reaction).</span></span>
A chemical change can also be called a chemical reaction
Volatility is a chemical property. The other ones are chemical properties
Answer: The correct option is A.
Explanation: The given molecules are the molecules of same element.
These molecules are considered as diatomic species.
Polar molecules are the molecules in which some polarity is present in the bond. These molecules are formed when there is some difference in the electronegativities of the elements. Example: HCl
Non-polar molecules are the molecules where no polarity is present in the bond. These molecules are formed when there is no difference in the electronegativities of the elements. Example: 
The given molecules are non-polar in nature.
Hence, these molecules must be non-polar. So, the correct option is A.