Equilibrium Shifts When Adding B(g) to A+B System

[disneychannel]

Homework Statement

What factors will change when additional B(g) is added to the following system at equilibrium.
Overall Reaction: A(g) + B(g) $\Leftrightarrow$(g)

The Attempt at a Solution

I said decreases, [A] decreases, [C] increases, and equilibrium will shift to the right...but i got it wrong...why and what would it be then?

 

[chemisttree]

If additional B is added, the last thing I would posit is that B would decrease. Everything else you have seems correct.

 

[disneychannel]

then why would A decrease...

 

[chemisttree]

When more product is made, it requires A to do so. A decreases. I believe your actual difficulty is one of initial conditions. You've assumed that the initial conditions are at a point after the addition of extra B and before the new mixture comes to equilibrium but the question assumes it is before B is added.
It appears that you have a good grasp of the concept so relax and don't debate semantics. You'll get nowhere with that.

 

[disneychannel]

Okay! Thank You!