Explanation:
Part a
Pyridine is an aromatic heterocyclic compound and undergoes nucleophilic aromatic substitution reaction at 2 and 4 positions.
This is because, when a nucleophile attack pyridine at 2 and 4 positions, the anoin formed is stabilized. In the anion formed is tabilized by resonance and also negative charge is present at electronegative atom, nitrogen.
If the nucleophile attack at 3 position, the anion formed is not as stable as anions formed when nucleophile attach at 2 and 4 positions. This is because negative charge is not present at the nitrogen atom.
Part b:
Tautomers are structural isomers of each others formed by migration atom within the molecule. Tautomers exist in equilibrium with each other.
Tautomers of 2-Hydroxypyridine and 4-Hydroxypyrine are given in the attachment.
Since you didn't have any extra information about the question I'll be presenting an example from my own textbooks that I've used.
An example of a direct observation is listening to a cricket chirp at night, and counting the number of chirps per minute.
Direct Observation is where the evaulator watches the subject in their usual habitat without disrupting or altering it.
Answer:
Explanation:
Due to Coulomb´s law electric force can be described by the formula 
, where K is the Coulomb´s constant (
), 
= Charge 1 (Na+ in this case), 
is the charge 2 (Cl-) and r is the distance between both charges.
Work made by a force is W=F.d and total work produced is the change in energy between final and initial state. this is 
.
so we have ![W=W_{f} -W_{i} =(K\frac{q_{(Na+)}q_{(Cl-)}rf}{r_{f} ^{2}})-(K\frac{q_{(Na+)}q_{(Cl-)}ri}{r_{i} ^{2}})=Kq_{(Na+)}q_{(Cl-)[\frac{1}{{r_{f}}} -\frac{1}{{r_{i}}}]](https://tex.z-dn.net/?f=W%3DW_%7Bf%7D%20-W_%7Bi%7D%20%3D%28K%5Cfrac%7Bq_%7B%28Na%2B%29%7Dq_%7B%28Cl-%29%7Drf%7D%7Br_%7Bf%7D%20%5E%7B2%7D%7D%29-%28K%5Cfrac%7Bq_%7B%28Na%2B%29%7Dq_%7B%28Cl-%29%7Dri%7D%7Br_%7Bi%7D%20%5E%7B2%7D%7D%29%3DKq_%7B%28Na%2B%29%7Dq_%7B%28Cl-%29%5B%5Cfrac%7B1%7D%7B%7Br_%7Bf%7D%7D%7D%20-%5Cfrac%7B1%7D%7B%7Br_%7Bi%7D%7D%7D%5D)
Given that ri= 1.1nm= 
and rf= infinite distance
![W=(9x10^{9})(1.6x10^{-19})(-1.6x10^{-19})[\frac{1}{\alpha }-\frac{1}{(1.1x10^{-9})}]=2.1x10^{-19}J](https://tex.z-dn.net/?f=W%3D%289x10%5E%7B9%7D%29%281.6x10%5E%7B-19%7D%29%28-1.6x10%5E%7B-19%7D%29%5B%5Cfrac%7B1%7D%7B%5Calpha%20%7D-%5Cfrac%7B1%7D%7B%281.1x10%5E%7B-9%7D%29%7D%5D%3D2.1x10%5E%7B-19%7DJ)
Answer:
Saturated solution = 180 gram
Explanation:
Given:
Solubility of Z = 60 g / 100 g water
Given temperature = 20°C
Amount of water = 300 grams
Find:
Saturated solution
Computation:
Saturated solution = [Solubility of Z] × Amount of water
Saturated solution = [60 g / 100 g] × 300 grams
Saturated solution = [0.6] × 300 grams
Saturated solution = 180 gram
Answer:
In engineering and science the common stand is two places.
For example if you get a calculation of 4.567 round up and give the result of 4.57
