<span>polar, Hadley, Ferrel, polar, Hadley, Ferrel. I hope this helps you.</span>
Answer:
Hydrogen is collected by downward displacement of water as it is less denser than water. Hence it comes out at the surface of water . It is insoluble in water so it does not dissolve in water
<u>Answer:</u> The half life of the reaction is 1190.7 seconds
<u>Explanation:</u>
The equation used to calculate rate constant from given half life for first order kinetics:

where,
k = rate constant of the reaction = 
= half life of the reaction = ?
Putting values in above equation, we get:

Hence, the half life of the reaction is 1190.7 seconds
There are 115 known elements as of today (Feb. 13, 2016)
so, 'C' is the correct answer