Calculate the volume of $CO_2$ at $NTP$ that can be obtained by heating $200 \ g$ of $80 \%$ pure $CaCO_{3(s)}$.

Calculate the approximate mass (in $g$) of $H_2S$ required for the following reaction when $15 \ L$ of oxygen at $STP$ reacts completely.
$2 H_2S_{(g)} + 3 O_{2(g)} \longrightarrow 2 SO_{2(g)} + 2 H_2O_{(g)}$
(molar mass of $H_2S = 34 \ g \ mol^{-1}$)

Under the same conditions of temperature and pressure,the ratio of the masses of equal volumes of $O_2$,$O_3$,and $SO_2$ will be respectively .............

To $50 \ mL$ of $0.1 \ N \ Na_2CO_3$ solution,$150 \ mL$ of water is added. What is the molarity of the resultant solution?

$A$ solid mixture weighing $5 \ g$ contains equal number of moles of $Na_2CO_3$ and $NaHCO_3$. This solid mixture was dissolved in $1 \ L$ of water. What is the volume (in $mL$) of $0.1 \ M \ HCl$ required to completely react with this $1 \ L$ mixture solution?

$A$ solution contains $1.2046 \times 10^{24}$ hydrochloric acid molecules in one $dm^3$ of the solution. The strength of the solution is .......... $N$.