An explanation for a MC answer, pls :) (1 Viewer)

[smelnizzle]

the answer is D, and i have no idea why or how. D:

 

[eriito]

(10^-8.6)/(10^-10)
=25ish

 

[brenton1987]

the answer is D, and i have no idea why or how. D:

The colourless bar extends from pH 0 to pH 8.6 while the magenta bar extends from pH 10 to pH 14. So the region of colour change extends from pH 8.6 to pH 10.

The pH scale is logarithmic so the gap between pH 9 and pH 10 translates to a 10 fold change in proton concentration. The gap between pH 8 and pH is a 100 fold concentration. So already option A and B are wrong.

The colour change has a range of 1.4 pH units.
10^1.4 = 25 (D)

 

[smelnizzle]

ah!

thanks guys - both ways make sense.