Chemistry - Chemical Equilibrium Question with Solution | TestHub

$$\begin{array}{c}\text{Both}\text{constants}\text{are}\text{very}\text{large,}\text{so}\text{A}\text{is}\text{almost}\text{completely}\text{used:}\text{[A]}\approx \text{0}\text{Mass}\\ \text{balance:}\text{[B]}\text{+}\text{[C]}\text{=}\text{5,}\text{[D]}\text{+}\text{[E]}\text{=}\text{5,}\text{[A]}\text{+}\text{[C]}\text{+}\text{[E]}\text{=}\text{5}\\ \text{With}\text{[A]}\approx \text{0:}\text{[C]}\text{+}\text{[E]}\text{=}\text{5,}\text{so}\text{[B]}\text{=}\text{[E]}\text{=}\text{x}\text{and}\text{[D]}\text{=}\text{[C]}\\ {\text{K}}_{\text{1}}{\text{/K}}_{\text{2}}\text{=}\text{([C]/[B])/([E]/[D])}\text{=}\text{4}\\ \text{([C]/x)/(x/[C])}\text{=}{\text{[C]}}^{\text{2}}{\text{/x}}^{\text{2}}\text{=}\text{4,}\text{so}\text{[C]}\text{=}\text{2x}\\ \text{2x}\text{+}\text{x}\text{=}\text{5,}\text{so}\text{x}\text{=}\text{5/3}\\ \text{150x}\text{=}\text{250,}\text{written}\text{as}\text{0250}\end{array}$$