The enthalpy of a binary liquid mixture containing components $1$ and $2$ at $298$ K and $1$ bar is given by

H $=400$ x$1+600$ x$2+$ x$1$ x$2(40$ x$1+20$ x$2)$

Where H is in J$/$mol$.$ Obtain expression for partial molar enthalpies of H$1$ and H$2$ in terms of x$1$ and the numerical values of the pure component enthalpies H$1$ and H$2.$ Determine the partial molar enthalpies of component $1$ and $2$ at infinite dilution