- Joined
- May 10, 2013
- Messages
- 74
- Reaction score
- 7
If the Ka of the HClO is 33 x 10^-8, the Kb value of ClO- is:
A. 3 x 10^-7
B. 3.3 x 10^8
C. 3.3 x 10^6
D. 14
Very simple question, but the decimals have me all worked up. I was able to figure this one out knowing that 1x10^-14 = Ka x Kb. All decimal places aside, knowing it must be equivalent to an integer of 1, I was able to reason that 33x3 = 99 which is approx 100 (a factor of 1) and 33x3.3 would be greater than 1. However when I try to solve it, I can't seem to get the right exponent doing it in my head. Kb = (1x10^-14)/(33x10^-8), I re-wrote as (100x10^-12)/(33x10^-8) then dividing I get 3^(-12- -8) = 3^-4, the correct answer choice A which has it to the ^-7. I thought maybe I should have written it as 100x10^-16 and not 100x10^-12, but that would be 3x10^-8, still not 10^-7.
A. 3 x 10^-7
B. 3.3 x 10^8
C. 3.3 x 10^6
D. 14
Very simple question, but the decimals have me all worked up. I was able to figure this one out knowing that 1x10^-14 = Ka x Kb. All decimal places aside, knowing it must be equivalent to an integer of 1, I was able to reason that 33x3 = 99 which is approx 100 (a factor of 1) and 33x3.3 would be greater than 1. However when I try to solve it, I can't seem to get the right exponent doing it in my head. Kb = (1x10^-14)/(33x10^-8), I re-wrote as (100x10^-12)/(33x10^-8) then dividing I get 3^(-12- -8) = 3^-4, the correct answer choice A which has it to the ^-7. I thought maybe I should have written it as 100x10^-16 and not 100x10^-12, but that would be 3x10^-8, still not 10^-7.
