What weight of $SO_2$ can be made by burning sulphur in $5.0 \ mol$ of oxygen?

What volume of decimolar solution should be mixed in a solution of the same solute $(0.5 \, M, \, 200 \, mL)$ to make it $0.25 \, M$?

Haemoglobin contains $0.33\%$ of iron by weight. The molecular weight of haemoglobin is approximately $67200$. The number of iron atoms (At. wt. of $Fe = 56$) present in one molecule of haemoglobin is

Commercial concentrated sulfuric acid is $95\% $ $H_2SO_4$ by weight. If the density of this commercial acid is $1.834 \ g \ cm^{-3}$,the molarity of this solution is ....... $M$.

$A$ mixture of $2.3 \ g$ formic acid and $4.5 \ g$ oxalic acid is treated with conc. $H_2SO_4$. The evolved gaseous mixture is passed through $KOH$ pellets. Weight of the remaining product at $STP$ is .......... $g$.

For the combustion reaction of $1 \, mol$ of a hydrocarbon $C_xH_y$,the coefficients of $O_2$,$CO_2$,and $H_2O$ involved are respectively: