In the reaction $2P_2O_5 + 2HNO_3 \to P_4O_{10} + X$,what is the product $X$?

$108 \ g \ Al$ and $213 \ g \ MnO$ were heated to initiate the reaction:
$2 Al + 3 MnO \to Al_2O_3 + 3 Mn$
Which of the following is correct? (Atomic weights: $Mn = 55$,$Al = 27$)

For the gaseous reaction $H_2 + Cl_2 \rightarrow 2HCl$,if $20 \ mL$ of $H_2$ and $30 \ mL$ of $Cl_2$ are taken initially,the volume of $HCl$ formed and the volume of unreacted $Cl_2$ are respectively .....

Calculate the amount of carbon dioxide produced when:
$(i)$ $1$ mole of carbon is burnt in air.
$(ii)$ $1$ mole of carbon is burnt in $16 \ g$ of dioxygen.
$(iii)$ $2$ moles of carbon are burnt in $16 \ g$ of dioxygen.

Calculate the mass of $AgCl$ precipitated when $25 \ mL$ of $35 \%$ solution of $AgNO_3$ and $25 \ mL$ of $11.6 \%$ solution of $NaCl$ are mixed. (in $g$)

Calculate the weight of $FeO$ produced from $6.7 \ g$ of $VO$ and $4.8 \ g$ of $Fe_2O_3$ using the reaction: $2VO + 3Fe_2O_3 \rightarrow 6FeO + V_2O_5$ $(V = 51, Fe = 56)$ (in $g$)