A solution of two components containing $n_1$ moles of the $1^{\text {st }}$ component and $n_2$ moles of the $2^{\text {nd }}$ component is prepared. $M_1$ and $M_2$ are the molecular weights of component 1 and 2 respectively. If d is the density of the solution in $\mathrm{g} \mathrm{mL}^{-1}, \mathrm{C}_2$ is the molarity and $\mathrm{x}_2$ is the mole fraction of the $2^{\text {nd }}$ component, then $\mathrm{C}_2$ can be expressed as