Sapling #7 Week 2

[Rachel Kwan 1B]

For context here is the question: HClO is a weak acid ( Ka=4.0×10−8 ) and so the salt NaClO acts as a weak base. What is the pH of a solution that is 0.045 M in NaClO at 25 °C?

My specific question is why do you use the equation Cl0- + H20 [equilibrium arrows] HCl0 + OH-? Why don't you use the equation involving NaClO?

[Manseej Khatri 2B]

In solution Na+ and ClO- disassociate, with ClO- being the weak base (the conjugate of HClO4). The sodium does not participate in the reaction. The reaction could thus be represented as . The sodium cancel leaving the resulting equation.

[jeffrey van 2I]

Would we use the Ka value given to find the pH, or do we need to convert the Ka value to Kb since the equation involves a base?

[Kareena Patel 1G]

Would we use the Ka value given to find the pH, or do we need to convert the Ka value to Kb since the equation involves a base?

You would need to convert it to Kb because it involves a base.

[jeffrey van 2I]

Thanks, so just to confirm, I would just divide the value of Kw (1.0E-14) by the given Ka, right?

[Joseph Hsing 2C]

Thanks, so just to confirm, I would just divide the value of Kw (1.0E-14) by the given Ka, right?

Yup this is correct in order to find Kb.