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 $n$?

How many moles of $H_2O$ (per mole of $Cl_2$ evolved) will be formed when $KMnO_4$ is added to $HCl$ solution?

Mass of $NaOH$ required for formation of $100 \ mL$ of its decimolar solution is .............. $g$.

Six volumes of oxygen,on complete ozonisation,form ...... volumes of ozone.

$29.2 \% (w/w)$ $HCl$ 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 :

The amount of $50\% \ (w/w)$ solution of hydrochloric acid required to react with $200 \ g$ of $CaCO_3$ would be (in $g$)