Calculate the pH of a 2.0 m solution of Nh4cl [kb (nh3) =1.8 * 10^-5]

The ph of the given solution of NH4Cl is -0.504.

Explanation:

                                            Ka Kb = Kw

                                            Ka = Kw / Kb,

Kw = 1 10^-14

Kb of NH3 = 1.8 10^-5

We eventually want [H3O+] to calculate pH, so determine the Ka of NH3 from Kb  

The Kb for NH3 is 1.8 10^-5  

                                       Ka = (1 10^-14) / Kb

                                       Ka = (1 10^-14) / ( 1.8 10^-5)

                                       Ka = 5.56 10^-10

                                    NH4+ + H2O ↔ NH3 + H3O+

Calculate [H3O+] using the Ka equation:

                                        Ka = [NH3] [H3O+) / [NH4+]

We know that [NH3] = [H3O+] , and that [NH4+] = 2.0 M

                                        Ka = [H3O+]² / 2.0

                      5.56 10^-10 = [H3O+]²/ 2.0

                               [H3O+]² = (5.56 10^-10) 2.0

                               [H3O+]² = 10.227

                                 [H3O+] = 3.198

                                         pH = -log [H3O+]

                                        pH = -log 3.198

                                        pH = -0.504

sure im new too!

explanation:

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.