\({K_c} = \frac{{[{P_4}{O_{10}}(s)]}}{{[{P_4}(s)]{{[{O_2}(g)]}^5}}}\)
We know that concentration of a solid component is always taken as unity
\({K_c} = \frac{1}{{{{[{O_2}]}^5}}}\)
$II: C + D $ $\rightleftharpoons$ $ 3A ; K_{eq}= K_2, $
$III: 6B + D $ $\rightleftharpoons$ $2C; K_{eq} = K_3$ જેથી,