If $0.4 \ g$ of $NaOH$ is present in $40 \ mL$ of solution,what will be the molarity and normality? (Molecular weight of $NaOH = 40$)

$28 \ g$ $KOH$ is required to completely neutralize $CO_2$ produced on heating $60 \ g$ of impure $CaCO_3$. The percentage purity of $CaCO_3$ is approximately (molar masses of $KOH$ and $CaCO_3$ are $56$ and $100 \ g \ mol^{-1}$, respectively).

For a reaction,$N_2O_{5(g)} \rightarrow 2NO_{2(g)} + \frac{1}{2}O_{2(g)}$ in a constant volume container,no products were present initially. The final pressure of the system when $50\%$ of the reaction is completed is:

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 $= 1.83 \, g/mL$)

Upon mixing $50.0 \ mL$ of $0.1 \ M$ lead nitrate solution with $50 \ mL$ of $0.05 \ M$ chromic sulphate solution,precipitation of lead sulphate takes place. How many moles of lead sulphate are formed and what is the molar concentration of chromic sulphate left in the solution?

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 $n$?