When you reacted the zinc with the hydrochloric acid, you collected the hydrogen gas by water displacement. if the pressure in the room were 735 mm hg, and the partial pressure of the water were 22 mm hg, what would be the partial pressure of the hydrogen gas?

713mmHg

Explanation:

By using Dalton's law of partial pressure, the pressure outside the gas container is equal to the pressure inside it and this pressure equals the sum of the pressures of water and the gas.

i.e, P(total) = P(gas) + P(water)

P(gas) = P(total) - P(water)

P(gas) = 735 - 22

P(gas) = 713mmHg

here we have to get the change of moles on decrease the volume of the reaction in gas phase.

the   per the given options it will decrease by (d) 11-50%

we know, on decreasing the volume of the gas phase reaction the reaction moves to the product side.

the reaction:                     so₂cl₂ (g) = so₂ (g) + cl₂ (g)         total

the moles at equilibrium:   1 - α                 α               α           = 1+α

concentrations:                   1 - α               α               α           = 1 + α

(concentration = moles/volume, as volume is 1 l)

(where α is the degree of dissociation)

now the dissociation constant in terms of concentration is :

=  

or,

or,   = (at v = 1l)

the reaction:                     so₂cl₂ (g) = so₂ (g) + cl₂ (g)         total

the moles at equilibrium:   1 - α                 α               α           = 1+α

concentrations:               (1 - α)/0.5           α/0.5         α/0.5       = (1 + α)/0.5

thus, the dissociation constant in terms of concentration is :

or,  

=  

so, the change of 1 : 1/0.5

or, 1: 2

thus it will decrease by 50%.

or, as per the given options it will decrease by 11-50%