Question

Find the [OH−] of a 0.32 M methylamine (CH3NH2) solution. (The value of Kb for methylamine (CH3NH2) is 4.4×10−4.) Express your answer to two significant figures and include the appropriate units.

Answer 1

To find the hydroxide ion concentration, use the equation for the base ionization constant (Kb) and the given values to calculate [OH-].

Step-by-step explanation:

To find the hydroxide ion concentration of a 0.0325 M solution of ammonia (NH3), we can use the equation for the base ionization constant (Kb) and the fact that water dissociates to produce hydronium (H3O+) and hydroxide (OH-) ions.

Kb = [OH-][NH3] / [NH4+]

Given that Kb for ammonia is 1.76 x 10⁻⁵, we can rearrange the equation to solve for [OH-].

[OH-] = Kb * [NH4+] / [NH3]

Plugging in the given values, we have [OH-] = (1.76 x 10⁻⁵) * (0.0325) / (0.0325)

Simplifying, we find that [OH-] = 1.76 x 10⁻⁵ M.