What will be the normality of a solution containing $4.9 \ g$ of $H_3PO_4$ dissolved in $500 \ mL$ water (in $N$)?

The amount of iron $(Fe)$ in $g$ which can be produced from $600 \ g$ of magnetite ore is [Atomic mass of $Fe$ : $55.8$]

What weight of sodium hydroxide is required to neutralise $100 \ mL$ of $0.1 \ N - HCl$ (in $g$)?

$A$ mixture of $H_2$ and $O_2$ at $1 \, atm$ pressure contains $20 \%$ by weight of $H_2$. Find out the partial pressure of $H_2$ in $atm$.

$100 \ mL$ of $H_{2(g)}$ and $100 \ mL$ of $Cl_{2(g)}$ were allowed to react at $1 \ bar$ pressure as: $H_{2(g)} + Cl_{2(g)} \longrightarrow 2 HCl_{(g)}$. What will be the $PV$ type of work done during the reaction?

An aqueous solution of $18 \ g$ oxalic acid $(H_2C_2O_4 \cdot 2H_2O)$ is made up to $400 \ mL$. Calculate the volume of $0.1 \ M \ NaOH$ required to completely neutralize $50 \ mL$ of the above solution in $mL$.