The maximum amount of $BaSO_4$ precipitated on mixing equal volumes of $BaCl_2$ $(0.5 \ M)$ with $H_2SO_4$ $(1 \ M)$ will correspond to ................. $M$.

$100 \ g$ of propane is completely reacted with $1000 \ g$ of oxygen. The mole fraction of carbon dioxide in the resulting mixture is $x \times 10^{-2}$. The value of $x$ is ..... .
(Nearest integer)
[Atomic weight : $H=1.008$ ; $C=12.00$ ; $O=16.00$ ]

One mole of nitrogen gas on reaction with $3.01 \times 10^{23}$ molecules of hydrogen gas produces

Equal weights of $X$ (atomic weight $= 36$) and $Y$ (atomic weight $= 24$) are reacted to form the compound $X_2Y_3$. Which of the following is correct?

$CNG$ is an important transportation fuel. When $100 \, g$ of $CNG$ is mixed with $208 \, g$ of oxygen in vehicles,it leads to the formation of $CO_2$ and $H_2O$ and produces a large quantity of heat during this combustion. The amount of carbon dioxide produced in grams is ...... [nearest integer] [Assume $CNG$ to be methane]

Balance the following chemical equations:
$(i)$ $Cu_2S + O_2 \to Cu_2O + SO_2$
$(ii)$ $Ca_3(PO_4)_2 + H_2SO_4 \to Ca(H_2PO_4)_2 + CaSO_4$