A reactor is used to remove Siz from a wafer in semiconductor manufacturing by contacting the SiOz surface with HF$.$ The reactions are

$6$ HF $($g$)+$ SiOz$($s$)->$ HSiF$6($l$)+2$ H$2$O$(1)$

HSiFol$)->$ SiF$4($g$)+2$ HF $($g$)$

Assume the reactor is loaded with wafers having a silicon oxide surface, a flow of $50\%$ HF and $50\%$ N$2$ is started. At steady$-$state, the effective fractional conversion of HF is $10\%,$ and all of the HSiF formed in the first reaction reacts in the second reaction. What is the composition of the gaseous exhaust stream?