$19 \ g$ of a mixture containing $NaHCO_3$ and $Na_2CO_3$ on complete heating liberated $1.12 \ L$ of $CO_2$ at $STP$. The weight of the remaining solid was $15.9 \ g$. What is the weight (in $g$) of $Na_2CO_3$ in the mixture before heating?

The volume of $0.1 \, N$ dibasic acid sufficient to neutralize $1 \, g$ of a base that furnishes $0.04 \, mole$ of $OH^{-}$ in aqueous solution is ............ $mL$

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 .............

How much volume of $1 \,N$ aqueous solution of $H_2SO_4$ should be taken, which will contain $0.2$ moles of $H_2SO_4$ (in $\,mL$)?

$A$ $10 \ g$ effervescent tablet containing sodium bicarbonate $(NaHCO_3)$ and oxalic acid $(H_2C_2O_4)$ releases $0.25 \ L$ of $CO_2$ at $T = 298.15 \ K$ and $p = 1 \ bar$. If the molar volume of $CO_2$ is $25.0 \ L \ mol^{-1}$ under these conditions,what is the percentage by mass of sodium bicarbonate in each tablet? [Molar mass of $NaHCO_3 = 84 \ g \ mol^{-1}$,Molar mass of $H_2C_2O_4 = 90 \ g \ mol^{-1}$]

If isobutane and $n$-butane are present in a gas,then how much oxygen should be required for the complete combustion of $5 \ kg$ of this gas?