That's the answer on that picture
Answer:
Two Half-lives
Explanation:
Let number of Parent nuclei Initially present be X,
Then, finally 
Parent nuclei Will remain with 
daughter nuclei.
In one half- life , parent nuclei becomes half of initial.
So, starting with X parent nuclei,
After one half-life, it will degrade to 
.
After another half life , Parent nuclei will become half of
Which is equal to .
So, Parent nuclei have to go through Two half-lives.
Answer:
- <em><u>Step 2 (the slow step).</u></em>
Explanation:
The rate-determining step is always the slow step of a mechanism.
That is so, because it is the slow step which limits the reaction.
Imaging that for assembling a toy you have process of three steps:
- 1. order ten pieces, which you can do in 1 minute: meaning that you can order order the pieces for 60/1 = 60 toys in 1 hour.
- 2. glue the pieces and hold the toy until the glue hardens, which takes 1 hour: meaning finishingh 1 toy in 1 hour.
- 3. pack the toy, which takes 2 minutes: meaning that you can pack 60/2 = 30 toys in one hour.
The time to glue and hold one toy until the glue hardens determines that you can assemble 1 toy in 1 hour and not 60 toys or 30 toys.
Thus, the step that determines the rate at which the reaction happens is the slowest step: step 2.
