The molarity of $2 \, N \, HCl$ is .......

Hardness of water is $200 \ ppm$. Calculate the molarity and normality of $CaCO_3$ in the water.

What is the value of percent atom economy if the formula weight of the product is $46 \ u$ and the sum of the formula weight of all reactants is $92 \ u$ (in $\%$)?

What is the weight of the precipitate formed when $50 \ mL$ of $16.9 \%$ $AgNO_3$ solution is mixed with $50 \ mL$ of $5.8 \%$ $NaCl$ solution (in $g$)?

$100 \, mL$ of a given $H_2O_2$ sample in water (density $1.08 \, g/mL$) required $5 \, mL$ of $M/25 \, KMnO_4$ in acidic medium for its oxidation. Select the correct statement regarding $H_2O_2$ in the sample:

What will be the volume of $CO_2$ at $S.T.P.$ obtained by heating $9.85 \ g$ of $BaCO_3$? (Atomic mass of $Ba = 137$)