If one wants to make methanol out of synthesis gas,what should be the ratio of the gaseous components in the synthesis gas?

In the reaction,$2Al_{(s)} + 6HCl_{(aq)} \rightarrow 2Al^{3+}_{(aq)} + 6Cl^{-}_{(aq)} + 3H_{2(g)}$

$20 \ mL$ of $0.2 \ M \ Al_2(SO_4)_3$ is mixed with $20 \ mL$ of $6.6 \ M \ BaCl_2$. The concentration of $Cl^{-}$ ion in the final solution is $......... \ M$.

$8 \ g$ of $H_2$ and $256 \ g$ of $HI$ are in a $4 \ L$ flask. Calculate their active mass. $(H = 1 \ g \ mol^{-1}, I = 127 \ g \ mol^{-1})$

For preparing $0.05 \ N \ H_2SO_4$ solution in one litre,we need $H_2SO_4$. (in $g$)

When $CO_2\,(g)$ is passed over red hot coke,it partially gets reduced to $CO\,(g).$ Upon passing $0.5\,L$ of $CO_2\,(g)$ over red hot coke,the total volume of the gases increases to $700\,mL.$ The composition of the gaseous mixture at $STP$ is