A weak base is 1.3 % dissociated in its aqueous solution. If K_b for weak base is 1.69 10⁻⁵ at 298 K. Find the concentration of aqueous solution of weak base.

Step-by-step solution

For a weak base, the dissociation constant K_b is given by Ostwald's dilution law: K_b = C ^2 1 - Since the degree of dissociation = 1.3 % = 0.013 is very small ( 1 ), we can approximate 1 - 1 . The expression simplifies to: K_b = C ^2 Rearranging for concentration C : C = K_b ^2 Substituting the given values K_b = 1.69 10⁻⁵ and = 0.013 : C = 1.69 10⁻⁵ (0.013)^2 C = 1.69 10⁻⁵ 1.69 10⁻⁴ C = 10⁻¹ = 0.1 M Answer: 0.1 M