What volume in $mL$ of $96\% \, w/w \, H_2SO_4$ is required to prepare $2 \, L$ of $3 \, M \, H_2SO_4$ solution? (Density of $H_2SO_4$ solution $= 1.83 \, g/mL$)

$19 \ g$ of a mixture containing $NaHCO_3$ and $Na_2CO_3$ on complete heating liberated $1.12 \ L$ of $CO_2$ at $STP$. The weight of the remaining solid was $15.9 \ g$. What is the weight (in $g$) of $Na_2CO_3$ in the mixture before heating?

When a hydrated salt,$Na_2SO_4 \cdot nH_2O$,is heated,it loses $56\%$ of its weight and becomes anhydrous. What is the approximate value of $n$?

The mass of sodium acetate $(CH_3COONa)$ required to prepare $250 \ mL$ of $0.35 \ M$ aqueous solution is . . . . . . $g$. (Molar mass of $CH_3COONa$ is $82.02 \ g \ mol^{-1}$)

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A:$ $3.1500 \ g$ of hydrated oxalic acid dissolved in water to make $250.0 \ mL$ solution will result in $0.1 \ M$ oxalic acid solution.
Reason $R:$ Molar mass of hydrated oxalic acid is $126 \ g \ mol^{-1}$.
In the light of the above statements,choose the correct answer from the options given below:

$29.2 \% (w/w)$ $HCl$ stock solution has a density of $1.25 \ g \ mL^{-1}$. The molecular weight of $HCl$ is $36.5 \ g \ mol^{-1}$. The volume $(mL)$ of stock solution required to prepare a $200 \ mL$ solution of $0.4 \ M$ $HCl$ is :