Initially, 0.65 mol of pcl5 is placed in a 1.0 l flask. at equilibrium, there is 0.15 mol of pcl3 in the flask. what is the equilibrium concentration of pcl5? express your answer to two significant figures and include the appropriate units.

Answer : The equilibrium concentration of is, 0.50 M

Explanation : Given,

Initial moles of = 0.65 mole

Volume of solution = 1.0 L

Moles of at equilibrium = 0.15 mole

The balanced equilibrium reaction will be,

Initial moles     0.65        0         0

At eqm.           (0.65-x)     x         x

Moles of at equilibrium = x = 0.15 mole

Moles of at equilibrium = x = 0.15 mole

Moles of at equilibrium = (0.65-x) = (0.65-0.15) = 0.50 mole

Now we have to calculate the concentration of at equilibrium.

Formula used :

Therefore, the equilibrium concentration of is, 0.50 M

the answer is d. 74.02