Equilibrium constant Kp for the reaction P4(s) + 6Cl2(g) 4PCl3(l) Kp = 1/ P6Cl2 Kp = P4Cl3/ P6P4 Kp = P4Cl3/ (P6P4) (P6Cl2) Kp = 1/ (P6P4) (P6Cl2)

Explanation:

Equilibrium constant is defined as the ratio of pressure of products to the pressuure of reactants each raised to the power their stoichiometric ratios. It is expressed as  

For the given chemical reaction:

The expression for in terms of gaseous is written as:

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.