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 $H_2S = 34 \ g \ mol^{-1}$)

How many grams of $HCl$ are required to prepare $1500 \, mL$ of $0.1 \, N \, HCl$ aqueous solution?

The drain cleaner,Drainex contains small bits of aluminum which react with caustic soda to produce dihydrogen. What volume of dihydrogen at $20^{\circ} C$ and $1 \, bar$ will be released when $0.15 \, g$ of aluminum reacts?

The density of a gas at $STP$ is $2.86 \, g \, L^{-1}$. Which of the following is the gas?

Calculate the number of $Cl^{-}$ ions in $222 \ g$ anhydrous calcium chloride? (At. mass $Ca=40, Cl=35.5$)

Zinc reacts with hydrochloric acid to give hydrogen and zinc chloride. The volume of hydrogen gas produced at $STP$ from the reaction of $11.5 \ g$ of zinc with excess $HCl$ is $.......... \ L$ (Nearest integer) (Given: Molar mass of $Zn$ is $65.4 \ g \ mol^{-1}$ and Molar volume of $H_2$ at $STP = 22.7 \ L$)