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Equilibrium equation question

Here's the question-
2 moles of compound P were placed in a vessel. The vessel was heated and compound P was partly decomposed to produce Q and R. A dynamic equilibrium between P,Q,R was established.
At equilibrium x moles of R were present and the total number of moles present was (2+ x/2)
What is the equation for this equilibrium reaction
A) P <--> 2Q + R
B) 2P <--> 2Q + R
C) 2P <--> Q + R
D) 2P <--> Q + 2R

Please help me out!
Thank you
Original post by abhishekagarwal
Here's the question-
2 moles of compound P were placed in a vessel. The vessel was heated and compound P was partly decomposed to produce Q and R. A dynamic equilibrium between P,Q,R was established.
At equilibrium x moles of R were present and the total number of moles present was (2+ x/2)
What is the equation for this equilibrium reaction
A) P <--> 2Q + R
B) 2P <--> 2Q + R
C) 2P <--> Q + R
D) 2P <--> Q + 2R

Please help me out!
Thank you


The total moles is made of the remaining P and the moles of products.

In equation A if there are x mol of R, then moles of P = 2-x and moles of Q = 2x
Total moles = 2-x + x + 2x = 2 + 2x

Do this for the other equations ...
Original post by charco
The total moles is made of the remaining P and the moles of products.

In equation A if there are x mol of R, then moles of P = 2-x and moles of Q = 2x
Total moles = 2-x + x + 2x = 2 + 2x

Do this for the other equations ...


Thanks a ton!!! I have my exam tomorrow and you've saved me
I was just wondering that if we were not given the equations(4 choices) would it be possible or would there be many possible answers

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