$$\ce{2NOCl <=> 2NO + Cl2}$$
What will be the effect on equilibrium concentration of $\ce{NOCl}$ when equal moles of $\ce{NOCl}$ and $\ce{NO}$ are introduced in the mixture at constant temperature?
Now this is what I think
Increasing the moles will result in increased concentration of both $\ce{NOCl}$ and $\ce{NO}$. But there also lies a second product $\ce{Cl2}$. Since there's an increase in $\ce{NO}$ and $\ce{NOCl}$, there should be an equal increase in the concentration of $\ce{Cl2}$ to keep the equilibrium-constant constant. But since there's no addition of $\ce{Cl2}$ molecules there should be a decrease in $\ce{NOCl}$ concentration which will decompose further to increase the molar ratio of $\ce{Cl2}$ and hence achieve equilibrium. Please enlighten me where my logic is flawed.
From comments (edit by BuckThorn): The reported answer is that the position of equilibrium remains unchanged and hence the concentration of $\ce{NOCl}$ remains constant.