If the density of $1 \ mol$ of a gas at $NTP$ is $0.1784 \ g/L$,what is the weight of $1 \ mol$ of the gas in $g$?

As per the following equation, $0.217 \ g$ of $HgO$ (molecular mass $= 217 \ g \ mol^{-1}$) reacts with excess iodide. On titration of the resulting solution, how many $mL$ of $0.01 \ M$ $HCl$ is required to reach the equivalence point (in $mL$)?
$HgO + 4 I^{-} + H_2O \longrightarrow HgI_4^{2-} + 2 OH^{-}$

In the preceding question,the amount of $Na_2CO_3$ present in the solution is ............. $g$.

If $6.022 \times 10^{20}$ atoms are present in $100 \ mL$ of urea solution,then find out the molarity of the urea solution. (in $M$)

In a chemical reaction, the sum of the formula weights of all reactants is $274 \text{ u}$ and the atom economy is $50\%$. Calculate the formula weight of the desired product. (in $\text{ u}$)

Ammonia on reaction with chlorine forms an explosive $NCl_3$. What is the mole ratio of $NH_3$ and $Cl_2$ required for this reaction?