The charge that stays on an object is called<span> static </span>electricity<span />
It is either the 3rd answer or the 4th answer. Both are correct ways to write hydrates, but I was taught the 4th way. Just make sure this answer matches the format of the examples your teacher gave you.
<u>Answer:</u> The equilibrium constant expression for the given equation is written below.
<u>Explanation:</u>
Equilibrium constant in terms of partial pressure is defined as the ratio of partial pressures of products to the partial pressures of reactants each raised to the power their stoichiometric ratios. It is expressed as 
For the general chemical equation:

The expression of
follows:

For the given chemical equation:

The expression of
for above equation follows:

Hence, the equilibrium constant expression for the given equation is written above.