Commercially available concentrated Phosphoric acid has the following label specification:Formula: H$2$PO$4$ Density: $1\mathrm{.}88$ g$/$cm$^3$ IUPAC ID: Phosphoric acid Boiling point $158$C Melting point: $42\mathrm{.}35$deg C Molar mass: $97\mathrm{.}994$ g$/$mol Assay $85\%$

$1.$Using this label information calculate the normality of concentrated H$2$PO$4$

$2.$a$.$ A laboratory procedure calls for $250$ mL of $0\mathrm{.}4$ N H$2$PO$4.$ Describe how you would prepare this solution using a stock solution of concentrated H$2$PO$4$

b$)$ Estimate the concentration as mol$/$L of the solution made by dissolving $8\mathrm{.}40$g of FeCl$2.6$H$2$O and making it up to $100$mL in a volumetric flask. $[$ Atomic masses H $=1$; $0=16$; Cl $=35\mathrm{.}5$; Fe $=55\mathrm{.}85]$