How Does the Proton-Proton Cycle Result in the Formation of Helium?

[logearav]

Homework Statement

Dear members,
In proton proton cycle, Two protons fuse together to form a duetron with positron and nuetrino.
Then duetron combine with another proton to form ₂He³, which then combines with another ₂He³ to give ₂He⁴
The final reaction is
4₁H¹+2e^---> ₂He⁴

Homework Equations

3. The Attempt at a Solution
Only three protons fuse together in the process, then how in the final equation it has been stated 4 protons fuse. For ₂He³ to combine with ₂He³ , the reaction of proton fusing with another proton, giving duetron, which fusing with another proton, should happen twice. So it is 6 protons fusing. So why its been mentioned only 4 protons fuse to form helium. Please help revered members

 

[Redbelly98]

3. The Attempt at a Solution
Only three protons fuse together in the process, then how in the final equation it has been stated 4 protons fuse. For ₂He³ to combine with ₂He³ , the reaction of proton fusing with another proton, giving duetron, which fusing with another proton, should happen twice. So it is 6 protons fusing. So why its been mentioned only 4 protons fuse to form helium. Please help revered members

6 protons fuse to form 2 helium-3 nuclei. Then the two helium-3 nuclei form helium-4 plus 2 protons.

Alternatively, you might write a net reaction that doesn't include 2 of the original 6 protons -- in which case you wouldn't have the 2 protons that are left over in the end.

 

[logearav]

6 protons fuse to form 2 helium-3 nuclei. Then the two helium-3 nuclei form helium-4 plus 2 protons.

Alternatively, you might write a net reaction that doesn't include 2 of the original 6 protons -- in which case you wouldn't have the 2 protons that are left over in the end.

Thanks for the reply sir. But i didnt understand the lines quoted above.

 

[Redbelly98]

Is this a homework problem? I am having trouble understanding exactly what the problem is asking, or whether you are just trying to understand for yourself what happens in nuclear fusion.

 

[logearav]

Sir, i am asking to get clarified, because my teacher has not given satisfactory reply. I got 90% of what you said, but i can't understand the lines you have written which i quoted in my previous query.
Thanks again. This is the forum which gives excellent insights to physics, that's why i keep raising my query

 

[Redbelly98]

6 protons fuse to form 2 helium-3 nuclei. Then the two helium-3 nuclei form helium-4 plus 2 protons.

Okay, so omit the intermediate products (He-3 nuclei) and write that as

6 ¹H → ⁴He + 2 ¹H (+ energy, positrons, and neutrinos)​

We have hydrogen nuclei on both sides of the reaction, so we can take away 2¹H from each side. That leaves us with the net reaction.

 

[logearav]

Mr.Redbelly, Fantastic. I got it now. Thank you so much, sir