Answer: I found this online. Hope it helps you.
Explanation:
This pressure is transmitted throughout the liquid and makes it more difficult for bubbles to form and for boiling to take place. If the pressure is reduced, the liquid requires less energy to change to a gaseous phase, and boiling occurs at a lower temperature.
Alkanes are hydrocarbons that only contain single bonds in them. A carbon can bond with up to 4 atoms, even with another carbon atom. So, in a C-C bond, 3 more H atoms can bond to each of the C atom. Generally, the chemical formula for alkanes is CₓH₂ₓ₊₂. So for butane, there are 4 C atoms. The corresponding H atoms are 2(4) + 2 = 10. That's why it's chemical formula is C₄H₁₀.
Answer: first option is not a termination
∙CH3 + Cl2 → CH3Cl + Cl∙
Explanation:
Since a radical is formed as part of the product it means it's a propagation step and not a termination step, at termination no free radical exist as product
Answer: 
Explanation:
Electron gain enthalpy is defined as energy released on addition of electron to an isolated gaseous atom.
The amount of energy released will be maximum when the tendency to attract electrons is maximum. As flourine has atomic number of 9 and has electronic configuration of 2,7. It can readily gain 1 electron to attain stable noble gas configuration and hence liberates maximum energy.