Answer :-
<h3>
Water and Air are necessary for rusting .</h3>
Answer:
The answer to your question is below
Explanation:
See the attachment.
Synthesis ΔH
ΔH = 25 - (-30) = 25 + 30 = 55 kJ Endothermic reaction
Single reaction
ΔH = 30 - 65 = -35 KJ Exothermic reaction
Double reaction
ΔH = 60 - 10 = 50 kJ Endothermic reaction
In Alpha decay two neutrons and protons are lost, so the mass decreases by four and the atomic number decreases by two.
Therefore the correct answer is B: Ra-224.