How many grams of $KClO_3$ must be decomposed to obtain $2.40 \, L$ of $O_2$ gas at $25 \, ^\circ C$ and $740 \, mm \, Hg$ pressure (in $, g$)? (Molar mass of $KClO_3 = 122.5 \, g \, mol^{-1}$)

In an experiment,it was shown that $10 \ mL$ of a $0.05 \ M$ solution of a chloride required $10 \ mL$ of a $0.1 \ M$ solution of $AgNO_3$. Which of the following will be the formula of the chloride ($X$ stands for the symbol of the element other than chlorine)?

The same mass of $CH_4$ and $H_2$ is taken in a container. The partial pressure caused by $H_2$ is:

If equal masses of methane $(CH_4)$ and hydrogen $(H_2)$ are mixed in an empty container at $25\,^oC$,what is the fraction of the total pressure exerted by hydrogen?

What is the percent atom economy if the formula weight of reactants and the formula weight of products are $45 \ u$ and $35 \ u$ respectively (in $\%$)?

What volume of Hydrogen gas,at $273 \ K$ and $1 \ atm$ pressure,will be consumed in obtaining $21.6 \ g$ of elemental boron (atomic mass $= 10.8$) from the reduction of boron trichloride by Hydrogen? (Answer in $L$)