If the concentration of compound $AB_5$ is $10^{-3} \text{ mol/L}$,then the concentration of $B^{-}$ will be .......

The mass percentage composition of dry air at sea level is approximately $N_2: 63 \%$,$O_2: 16 \%$,$Kr: 21 \%$. If the total pressure is $p \ atm$,calculate the partial pressure of each component respectively. (Molecular weights: $N_2 = 28, O_2 = 32, Kr = 84$)

The density of $SO_2$ at $STP$ is ......... $g/L$.

$0.01$ mole of iodoform $(CHI_3)$ reacts with $Ag$ to produce a gas whose volume at $NTP$ is ............. $mL$.
$2CHI_3 + 6Ag \to 6AgI_{(s)} + C_2H_{2(g)}$

The volume of $0.6 \, M$ $NaOH$ required to neutralize $30 \, cm^3$ of $0.4 \, M$ $HCl$ is ........ $cm^3$.

For the combustion reaction $C_2H_{6(g)} + nO_{2(g)} \to CO_{2(g)} + H_2O_{(l)}$,what is the ratio of the stoichiometric coefficients of $CO_2$ and $H_2O$ in the balanced equation?