Answer:
To fulfill octet of B atom in borane, nucleophilic attack by pi electrons of alkene takes place with electrophilic B center in borane.
Explanation:
In Borane (), B atom has energetically vacant 2p orbital and thereby octet is incomplete.Therefore B center in borane act as an electrophilic center.
In alkene, pi bonding electrons are loosely bound together due to side on overlap of two constituent p-orbitals. Hence this pi bond can be easily broken. Alternatively, we can say that pi bond in alkene act as a potential nucleophile.
The first step of hydroboration occurs in a concerted manner where pi electrons of alkene first attack vacant 2p orbital of B in borane to fulfill it's octet (represented by an arrow drawn from alkene to B atom) and forms a 4 memebered cyclic intermediate. Simulaneously, a B-H bond in borane is donated to alkene through 3c-2e bond (3 center-2 electron bond).
Full mechanism has been shown below.
The answer would be 8 just took the test
Answer:
21
Explanation:
Let us count the number of individual atoms for Na2S2O3 (the compound name):
Na: 2
S: 2
O: 3
This brings us to a total of 7 atoms for one molecule of sodium thiosulfate. For three of these compounds, we get 3*7=21
Answer:
Here's what I find
Explanation:
You don't use ΔHfus. You use ΔHvap
There are some preliminary calculations:
- Use the density of the liquid to calculate its mass.
- Use the molar mass to calculate the moles (n)
The formula for the heat (q) absorbed during vaporization is
q = nΔHvap
Insert your numbers into the formula, do the calculation, and you have the answer.