JEE Catalysts

When $CO$ and $H_2$ mixture are made to react under different conditions different products are formed. When the above mixture is heated in $Ni$ at $600K$ $A(g)$ and $B(g)$ are produced. When the mixture of $CO$ and $H_2$ is heated in presence of $Cu$ $X(g)$ is produced. When $CO$ and $H_2$ is heated in $Cu, Zn$ , $Cr_2O_3$ $Y(g)$ is formed. If the sum of molecular mass of $A, B, X, Y$ is $Z$ . Enter $\sqrt {\frac {Z+2}{2}}$ as answer.