Which of the following should be done in order to prepare $0.40 \ M \ NaCl$ starting with $100 \ mL$ of $0.30 \ M \ NaCl$ (mol.wt. of $NaCl = 58.5$)?

$3.0$ molal $NaOH$ solution has a density of $1.110 \, g/mL$. The molarity of the solution is

$A$ mixture of sodium oxide $(Na_2O)$ and calcium oxide $(CaO)$ is dissolved in water and saturated with excess carbon dioxide $(CO_2)$ gas. The resulting solution is $......$ It contains $.........$ :

When a standard solution of $NaOH$ is left in air for a few hours:

State whether the following statements are true or false:
$(i)$ The molarity of a $0.6 \ N$ aqueous solution of ${H_3PO_3}$ is $1.2 \ M$.
$(ii)$ $\text{Empirical formula} = n \times \text{Molecular formula}$.
$(iii)$ In ${Cl_2O}$,the weight of chlorine combining with $8 \ g$ of oxygen is $35.5 \ g$.

Molarity of a $50 \ mL$ $H_2SO_4$ solution is $10.0 \ M$. If the density of the solution is $1.4 \ g/cc$, calculate its molality.