A chemical reaction happens when the atoms or molecules rearrange to form a new substance
Answer: The complete reaction is as follows.

Explanation:
When nucleus of two or more atoms are bombarded together then it leads to the formation of new particles with new identity. This type of reaction are called nuclear reaction.
For example, 
Here, nitrogen atom when bombarded with a neutron then it is forming hydrogen and a carbon atom.
As total atomic mass on reactant side is (14 + 1) = 15
So, the atomic mass of carbon formed on product side is (15 - 1) = 14.
The number of protons holded by this carbon atom is (7 - 1) = 6.
Therefore, we can conclude that the complete reaction is as follows.

Answer:
Explanation:
Molal freezing point depression constant of butanol Kf = 8.37⁰C /m
ΔTf = Kf x m , m is no of moles of solute per kg of solvent .
mol weight of butanol = 70 g
235.1 g of butanol = 235.1 / 70 = 3.3585 moles
3.3585 moles of butanol dissolved in 4.14 kg of water .
ΔTf = 8.37 x 3.3585 / 4.14
= 6.79⁰C
Depression in freezing point = 6.79
freezing point of solution = - 6.79⁰C .