What is the volume (in $dm^3$) occupied by $75 \ g$ of ethane at $S$.$T$.$P$.?

$20 \, cc$ of $CO_2$ are passed over red hot coke. The volume of $CO$ evolved is ............ $cc$.

The amount of metallic $Zn$ (atomic weight $= 65.4$) required to react with aqueous sodium hydroxide to produce $1 \ g$ of $H_2$ is $.... \ g$.

$20 \ mL$ 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 $......... \ M$.

One third litre of $x \ M \ K_2Cr_2O_7$ is required to completely oxidise $2 \ L$ of $0.1 \ M$ ferrous ammonium sulphate in acidic medium. What is $x$?

$X$ litres of carbon monoxide is present at $STP$. It is completely oxidized to $CO_2$. The volume of $CO_2$ formed is $11.207$ litres. What is the value of $X$ in litres?