## HW problem 12.69 (6th edition)

Sydney Takeda 2I
Posts: 62
Joined: Fri Sep 28, 2018 12:17 am

### HW problem 12.69 (6th edition)

Can someone explain how to work through this problem? I understand the calculations and everything, but would I need to look up the Ka value or??

Anusha 1H
Posts: 65
Joined: Fri Sep 28, 2018 12:15 am

### Re: HW problem 12.69 (6th edition)

(Sorry the tables I'm referring to are labeled this way in the 7th edition!)

Yes, for part a), you use the Kb value for NH3 in table 6C.2 to find the Ka value of its conjugate acid NH4+
(KaKb = Kw)

For part b), you can use table 6D.1 to find the Ka value of common cations in water, which includes Al3+ at 1.4 x 10^-5

Hope that helps!

Sydney Takeda 2I
Posts: 62
Joined: Fri Sep 28, 2018 12:17 am

### Re: HW problem 12.69 (6th edition)

Anusha 1C wrote:(Sorry the tables I'm referring to are labeled this way in the 7th edition!)

Yes, for part a), you use the Kb value for NH3 in table 6C.2 to find the Ka value of its conjugate acid NH4+
(KaKb = Kw)

For part b), you can use table 6D.1 to find the Ka value of common cations in water, which includes Al3+ at 1.4 x 10^-5

Hope that helps!

I guess I totally skimmed over the common cations table lol but thank you!!

Return to “Calculating pH or pOH for Strong & Weak Acids & Bases”

### Who is online

Users browsing this forum: No registered users and 1 guest