Question

Question #789fb

Answer 1

It is (.15 moles of k2s/liter) x (2 moles of K/ 1 mole of K2S) = .30 moles k/ liter.

Or

K2S -------> 2K+ + S2-

so [K+] = 2 X [K2S] = 2 X 0.15 = 0.3 M

You have 2 moles of K+ for every mole of K2S and Molarity (M) is Moles per Liter.