If $1/2 \text{ mole of oxygen reacts with aluminum to form } Al_2O_3, \text{ the mass of aluminum metal consumed in the reaction is } ..... \text{ g. } (Al=27)$

The mass of $CO_2$ that shall be obtained by heating $10 \ kg$ of $80\%$ pure limestone $(CaCO_3)$ is $:-$ (in $kg$)

$CaCO_3$ reacts with $HCl$ to produce $CaCl_2, CO_2$ and $H_2O$. The approximate mass (in $g$) of $CaCO_3$ required to react completely with $25 \ mL$ of $0.75 \ M \ HCl$ is (atomic mass of $Ca=40, C=12, O=16, Cl=35.5$ and $H=1$).

Combustion of $10 \ mL$ of a gaseous hydrocarbon gives $40 \ mL$ of $CO_2$ and $50 \ mL$ of water vapour under the same conditions. The molecular formula of the hydrocarbon is

$12 \ g$ of $Mg$ (atomic mass $24$) on reacting completely with acid gives hydrogen gas,the volume of which at $STP$ would be ............... $L$.

To change the strength of $25 \, mL$ of $0.15 \, M$ $HCl$ to $0.1 \, M$,the quantity of water that is to be added is.......$mL$