Answer:The ratio of the concentrations of 
and 
when the buffer has a pH of 7.02 is 0.69
Explanation:
The dissociation constant for formic acid = 
Concentration of HA= 0.5 mM
Concentration of = 0.1 mM
pH = 6.16
First we have to calculate the value of 
.
Using Henderson Hesselbach equation :
![pH=pK_a+\log \frac{[A^-}{[HA]}](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%20%5Cfrac%7B%5BA%5E-%7D%7B%5BHA%5D%7D)
Now put all the given values in this expression, we get:
![6.16=pK_a+\log (\frac{[0.1]}{0.5})](https://tex.z-dn.net/?f=6.16%3DpK_a%2B%5Clog%20%28%5Cfrac%7B%5B0.1%5D%7D%7B0.5%7D%29)
To calculate the ratio of the concentrations of and when the buffer has a pH of 7.02.
Using Henderson Hesselbach equation :
![7.02=6.86+\log \frac{[A^-]}{[HA]}](https://tex.z-dn.net/?f=7.02%3D6.86%2B%5Clog%20%5Cfrac%7B%5BA%5E-%5D%7D%7B%5BHA%5D%7D)
![\frac{[A^-]}{[HA]}=1.44](https://tex.z-dn.net/?f=%5Cfrac%7B%5BA%5E-%5D%7D%7B%5BHA%5D%7D%3D1.44)
![\frac{[HA]}{[A^-]}=0.69](https://tex.z-dn.net/?f=%5Cfrac%7B%5BHA%5D%7D%7B%5BA%5E-%5D%7D%3D0.69)
Thus the ratio of the concentrations of and when the buffer has a pH of 7.02 is 0.69
A doctor would treat it by having patients indulge in some pills
Answer:
D. the larva sheds its skin several times
Explanation:
At the end of the larval stage the insect will make a hard shell and inside it will become a pupa. At this stage the larva will stop eating and moving. The pupa appears lifeless, but one of Nature's most amazing transformations is happening.
Instead, according to a research team that looked at DNA samples from the two species and from black bears, the brown bear and polar bear ancestral lines have a common ancestor and split about 600,000 years ago.
