Answer:
A) homotopic and B) enantiotopic
Explanation:
Protons chemically equivalent are those that have the same chemical shift, also if they are interchangeable by some symmetry operation or by a rapid chemical process.
The existence of symmetry axes, Cn, that relate to the protons results in the protons being homotopic, that is chemically equivalent in both chiral and aquiral environments.
The existence of a plane of symmetry, σ, makes the protons related by it, are enantiotopic and these protons will only be equivalent in an aquiral medium; if the medium is chiral both protons will be chemically NOT equivalent. The existence of a center of symmetry, i, in the molecule makes the related protons through it enantiotopic and therefore chemically only in the aquiral medium.
Diastereotopic protons cannot be interconverted by any symmetry operation and they are different, with different chemical displacement.
Answer:
It matters
Explanation:
Pure substance are known to have a sharp freezing point. However, the presence of solute lowers the freezing point of the solvent. The best time to measure the freezing point is when the freezing process is just beginning.
It will be an error to measure the freezing point when the part of the solution has already frozen.
Explanation:
Early voyages to the East Indies
Sir James Lancaster commanded the first East India Company voyage in 1601 aboard the Red Dragon.
Fate: Nationalised:: Territories and responsibilities ceded to the British Government by ...
Founded: 31 December 1600; 420 years ago
Products: Cotton, silk, indigo dye, sugar, salt, spices, saltpetre, tea, and opium
Industry: Trade
Answer:
no correct answer please mention other answers.
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