Answer : The [α] for the solution is, -118.8
Explanation :
Enantiomeric excess : It is defined as the difference between the percentage major enantiomer and the percentage minor enantiomer.
Mathematically,

Given:
% major enantiomer = 86 %
% minor enantiomer = 14 %
Putting values in above equation, we get:


Now we have to calculate the [α] for the solution.
![[\alpha]=\text{Enantiomer excess}\times [\alpha]_{Pure}](https://tex.z-dn.net/?f=%5B%5Calpha%5D%3D%5Ctext%7BEnantiomer%20excess%7D%5Ctimes%20%5B%5Calpha%5D_%7BPure%7D)
![[\alpha]=0.72\times -165](https://tex.z-dn.net/?f=%5B%5Calpha%5D%3D0.72%5Ctimes%20-165)
![[\alpha]=-118.8](https://tex.z-dn.net/?f=%5B%5Calpha%5D%3D-118.8)
Thus, the [α] for the solution is, -118.8
Jets streams play a key role in determining the weather because they usually separate colder air and warmer air.
Answer:
a) Ka= 7.1 × 10⁻⁴; This is a weak acid because the acid is not completely dissociated in solution.
Explanation:
Step 1: Write the dissociation reaction for nitrous acid
HNO₂(aq) ⇄ H⁺(aq) and NO₂⁻(aq)
Step 2: Calculate the acid dissociation constant
Ka = [H⁺] × [NO₂⁻] / [HNO₂]
Ka = 0.022 × 0.022 / 0.68
Ka = 7.1 × 10⁻⁴
Step 3: Determine the strength of the acid
Since Ka is very small, nitrous acid is a weak acid, not completely dissociated in solution.
A. Cesium because reactivity of alkali metals increases from the top to the bottom of the group.