One and a half mole of oxygen combine with aluminium to form $Al_2O_3$. The weight of aluminium metal used in this reaction is .............. $g$ (Atomic weight of $Al = 27$).

For the combustion reaction of $1 \, mol$ of a hydrocarbon $C_xH_y$,the coefficients of $O_2$,$CO_2$,and $H_2O$ involved are respectively:

Gastric juice contains about $3.0 \ g$ of $HCl$ per liter. If a person produces about $2.6 \ liters$ of gastric juice per day,find the number of antacid tablets required to neutralize all the $HCl$ produced. Consider each antacid tablet contains $400 \ mg$ of $Al(OH)_3$. [Given,atomic masses: $Al=27, O=16, H=1, Cl=35.5$]

While combusting in air,$4 \ g$ of $H_2$ gas was completely converted into water. If $36 \ \mu mole$ of $CO_2$ from air is dissolved into that water,what is the concentration of $CO_2$?

What is the mass of potassium chloride produced when $12.25 \ g$ of potassium chlorate undergoes decomposition (in $g$)? (Atomic masses: $K=39, Cl=35.5, O=16$)

$40 \ mL$ of $0.1 \ N$ $KMnO_4$ is equivalent to $30 \ mL$ of $KHC_2O_4$ solution. How many $mL$ of $0.1 \ N$ $KOH$ are required to titrate $60 \ mL$ of the same $KHC_2O_4$ solution?