How many gram-equivalents of $NaOH$ are required to neutralize $25 \ cm^{3}$ of a decinormal $HCl$ solution?

The molarity of a $98\%$ by weight solution of $H_2SO_4$ is .......... $M$. The density of the solution at $35^o C$ is $1.84 \ g/cm^3$.

Complete combustion of $3 \ g$ of ethane gives $x \times 10^{22}$ molecules of water. The value of $x$ is ......... (Round off to the Nearest Integer). [Use: $N_{A} = 6.023 \times 10^{23} ;$ Atomic masses in $u$ $C = 12.0, O = 16.0, H = 1.0$]

If the density of iron is $7.86 \, g \, cm^{-3}$ and its atomic mass is $55.85 \, u$,then find the volume occupied by $1 \, mol$ of iron atoms in $cm^{3}$.

The mass of iron converted into $Fe_3O_4$ by the action of $18\text{ g}$ of steam is : (Given: Molar mass of $H$,$O$ and Fe are $1$,$16$ and $56\text{ g mol}^{-1}$ respectively). Assume iron is present in excess: (in $\text{ g}$)

$A$ cold drink bottle contains $200 \ mL$ liquid in which $CO_2$ is $0.1 \ M$. Considering $CO_2$ as an ideal gas,the volume of the dissolved $CO_2$ at $S.T.P$ is: (in $L$)