In the balanced combustion reaction of $1 \, mol$ of $C_xH_{2n-2}$ hydrocarbon,the coefficients of $O_2$,$CO_2$,and $H_2O$ will be respectively ...

Some $CO_2$ gas was kept in a sealed container at a pressure of $1 \ atm$ and at $273 \ K$. This entire amount of $CO_2$ gas was later passed through an aqueous solution of $Ca(OH)_2$. The excess unreacted $Ca(OH)_2$ was later neutralized with $0.1 \ M$ of $40 \ mL$ $HCl$. If the volume of the sealed container of $CO_2$ was $x$,then $x$ is $............. \ cm^3$ $(nearest \ integer)$.
$[$Given : The entire amount of $CO_{2(g)}$ reacted with exactly half the initial amount of $Ca(OH)_2$ present in the aqueous solution.$]$

Diatoms,microscopic organisms,are an abundant food source in the oceans producing carbohydrates from carbon dioxide and water by photosynthesis.
$6CO_2 + 6H_2O + \text{solar energy} \to C_6H_{12}O_6 + 6O_2$
$A$ blue whale gains $75 kg$ of mass per day by feeding on krill. The whale must consume ten times this mass of krill each day. The krill must consume $10.0 kg$ of diatoms to produce $1.0 kg$ of krill. Assuming that the mass gain of a whale's life is due to the consumption of carbohydrates $(C_6H_{12}O_6)$,calculate the moles of $CO_2$ that must be used by the diatoms to produce the carbohydrates consumed by a blue whale in a day.

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 $\%$)?

At $27\,^oC$,for the reaction,$N_2O_{4(g)} \to 2NO_{2(g)}$,the rate of reaction is $6 \times 10^{-3} \, atm \, min^{-1}$. Find the rate of the same reaction in terms of $mol \, L^{-1} \, min^{-1}$.

How many grams of $NaOH$ are equivalent to $100 \, mL$ of $0.1 \, N$ oxalic acid?