$25 \ cm^3$ of oxalic acid completely neutralized $0.064 \ g$ of sodium hydroxide. The molarity of the oxalic acid solution is: (in $M$)

In what ratio by mass carbon dioxide $(CO_2)$ and nitrogen $(N_2)$ should be mixed so that the partial pressure exerted by each gas is the same?

What is the ratio of the active masses of $22 \ g$ $CO_2$,$3 \ g$ $H_2$,and $7 \ g$ $N_2$ in a gaseous mixture?

Fortification of food with iron is done using $FeSO_4 \cdot 7 H_2 O$. The mass in grams of the $FeSO_4 \cdot 7 H_2 O$ required to achieve $12 \ ppm$ of iron in $150 \ kg$ of wheat is $..........$ (Nearest integer).
[Given: Molar mass of $Fe, S$ and $O$ respectively are $56, 32$ and $16 \ g \ mol^{-1}$]

What is the weight in $g$ of potassium chlorate $(KClO_3)$ required to produce the oxygen needed for the complete combustion of $84 \ L$ of $CO$ at $N.T.P$?

$10 \ mL$ of a gaseous hydrocarbon on combustion gives $40 \ mL$ of $CO_{2(g)}$ and $50 \ mL$ of water vapour. The total number of carbon and hydrogen atoms in the hydrocarbon is: