It's called a pH indicator.
Answer:
c is the answer then check it out
We assume that we have Ka= 4.2x10^-13 (missing in the question)
and when we have this equation:
H2PO4 (-) → H+ + HPO4-
and form the Ka equation we can get [H+]:
Ka= [H+] [HPO4-] / [H2PO4] and we have Ka= 4.2x10^-13 & [H2PO4-] = 0.55m
by substitution:
4.2x10^-13 = (z)(z)/ 0.55
z^2 = 2.31x 10^-13
z= 4.81x10^-7
∴[H+] = 4.81x10^-7
when PH equation is:
PH= -㏒[H+]
= -㏒(4.81x10^-7) = 6.32
Answer: 5.747 * 10^14 Hz
Explanation:
Convert 522nm to m = 522 * 10^-9 m (since 1nm=10^-9m)
If c = wavelength * frequency, where c is the speed of light (3.0 * 10^8 m/s), then you can manipulate the equation to solve for frequency (f).
f = c / wavelength
Plug in the given numbers:
f = (3.0 * 10^8) / (10^-9)
f = 5.747 * 10^14 Hz
