What is the mass of oxygen in $g$ required to produce enough $CO$ for the complete reduction of $1.6 \ kg$ of $Fe_2O_3$ (molar mass $= 160 \ g/mol$)?

Hydrogen gas is prepared in the laboratory by reacting dilute $HCl$ with granulated zinc. The following reaction takes place: $Zn + 2HCl \to ZnCl_2 + H_2$. Calculate the volume of hydrogen gas liberated at $STP$ when $32.65 \ g$ of zinc reacts with $HCl$. ($1 \ mol$ of a gas occupies $22.7 \ L$ volume at $STP$; atomic mass of $Zn = 65.3 \ u$).

How many liters of $H_2$ gas will be evolved at $STP$ by the reaction of zinc metal with $500 \, mL$ of $0.5 \, N \, HCl$?

Reaction of $x \ g$ of $Sn$ with $HCl$ quantitatively produced a salt. The entire amount of the salt reacted with $y \ g$ of nitrobenzene in the presence of the required amount of $HCl$ to produce $1.29 \ g$ of an organic salt (anilinium chloride) quantitatively.
$(1)$ The value of $x$ is. . . . .
$(2)$ The value of $y$ is. . . . .

$23 \ g$ of $Na$ metal reacts with ethanol to produce which of the following?

Concentrated aqueous sulphuric acid is $98\% \ H_2SO_4$ by mass and has a density of $1.80 \ g \ mL^{-1}$. The volume of acid required to make $1 \ L$ of $0.1 \ M \ H_2SO_4$ solution is ........ $mL$.