The molarity of a $0.2 \ N \ Na_2CO_3$ solution is ........ $M$.

The amount of water produced (in $g$) in the oxidation of $1$ mole of rhombic sulphur by conc. $HNO_3$ to a compound with the highest oxidation state of sulphur is. . . . . (Given data : Molar mass of water $= 18 \ g \ mol^{-1}$)

The normality of $1 \ M$ solution of $H_3PO_4$ will be.....$N$

$25 \ mL$ of a solution of $Na_2CO_3$ having a specific gravity of $1.25$ required $32.9 \ mL$ of a solution of $HCl$ containing $109.5 \ g$ of the acid per litre for complete neutralization. Calculate the volume of $0.84 \ N$ $H_2SO_4$ that will be completely neutralized by $125 \ g$ of the $Na_2CO_3$ solution (in $mL$).

What is the percent atom economy if the formula weight of reactants and the formula weight of products are $45 \ u$ and $35 \ u$ respectively (in $\%$)?

Calculate the amount of $CO_2$ gas produced when $32 \text{ g}$ of $CH_4$ is burned with a sufficient amount of oxygen. (Given: atomic weights of $C=12, O=16, H=1$) (in $\text{ g}$)