Answer:
Explanation: in exothermic reaction heat is released out
In endothermic reaction heat is absorbed
<u>Answer:</u> The molarity of citric acid that is commercially available lemon juice is 0.416 M
<u>Explanation:</u>
To calculate the concentration of acid, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is NaOH.
We are given:

Putting values in above equation, we get:

Hence, the molarity of citric acid that is commercially available lemon juice is 0.416 M
Magnesium would be more reactive.
Answer:
Intermolecular forces are the forces of attraction or repulsion which act between neighboring particles (atoms, molecules, or ions ). These forces are weak compared to the intramolecular forces, such as the covalent or ionic bonds between atoms in a molecule.
Importance:
Intermolecular forces are important because they determine the physical properties of substances. Many of the life-sustaining properties of water such as its high heat capacity are a result of the hydrogen bonding capabilities it has and are thus due to intermolecular forces.