To neutralise $20 \, mL$ of $M/10$ sodium hydroxide,the volume of $M/20$ hydrochloric acid required is .............. $mL$

When $500 \ mL$ of a gaseous hydrocarbon is burned in excess of $O_2$,it produces $2.5 \ L$ of $CO_2$ and $3.0 \ L$ of water vapor. What is the molecular formula of the hydrocarbon?

If a mixture of $340 \ g$ of $N_2$ and $H_2$ in the stoichiometric ratio yields $20\%$ $NH_3$ by mass,what is the mass of $NH_3$ produced in $g$?

What is the percentage atom economy during the conversion of reactant to product if the formula weight of reactants is $246 \ u$ and that of the product is $123 \ u$ (in $\%$)?

An aqueous solution of $4.5 \ g$ oxalic acid $(H_2C_2O_4)$ is made up to $250 \ mL$. Calculate the volume of $0.1 \ N$ $NaOH$ required to neutralize completely $20 \ mL$ of this solution.

At sea level,the dry air mass percentage composition is given as nitrogen gas: $70.0$,oxygen gas: $27.0$,and argon gas: $3.0$. If the total pressure is $1.15 \ atm$,calculate the ratio of the following respectively:
$(i)$ partial pressure of nitrogen gas to partial pressure of oxygen gas
$(ii)$ partial pressure of oxygen gas to partial pressure of argon gas
(Given: Molar mass of $N_2$,$O_2$,and $Ar$ are $28, 32$,and $40 \ g \ mol^{-1}$ respectively)