II. sulfur (S) and carbon (C)
and
III. fluorine (F) and oxygen (O)
will form covalent bonds, so the answer will be:
e. II and III
Explanation:
To know is what type of bond is formed between atoms we need to look at the electronegativity difference between the atoms.
If the electronegativity difference is less than 0.4 there is a nonpolar covalent bond.
If the electronegativity difference is between 0.4 and 1.8 there is a polar covalent bond. (if is a metal involved we consider the bond to be ionic)
If the electronegativity difference is greater then 1.8 there is an ionic bond.
We have the following cases:
I. lithium (Li) and sulfur (S)
electronegativity difference = 2.5 (S) - 1 (Li) = 1.5 but because there is a metal involved the bond will be ionic
II. sulfur (S) and carbon (C)
electronegativity difference = 2.5 (S) - 2.5 (C) = 0 so the bond will be nonpolar covalent
III. fluorine (F) and oxygen (O)
electronegativity difference = 4 (F) - 3.5 (O) = 0.5 so the bond will be polar covalent bond.
Learn more about:
covalent and ionic bonds
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Answer:
(c) The retention time would be higher (d) The retention time would be lower.
Explanation:
For the polar solutes which were separated using the hydrophilic interaction chromatography (HILIC) with a strongly polar bonded phase, the retention time would be higher if eluent were changed from 80 vol% to 90 vol% acetonitrile in water.
However, for the polar solutes which were separated using the normal-phase chromatography on bare silica with methyl t=butyl ether and 2-propanol solvent, the retention time would be lower if the eluent were changed from 40 vol% to 60 vol% 2-propanol.
Answer:
No net change in reaction occurs in this nucleophilic acyl subtitution reaction
Explanation:
Sodium ethoxide in ethanol gives nucleophilic acyl substitution reaction with ethyl-2-methylpropanoate.
Here ethoxide group replaces an ethoxide group from ester through addition-ellimination pathway.
So, ultimately, the product of this reaction is identical with reactant i.e. ethyl-2-methylpropanoate is reproduced.
Hence one might observe no change during reaction as product and reactant of this reaction are same.
Mechanistic pathway has been shown below.
Answer:
a lithium atom (Z=3, A=7 AMU) contains three protons (found from Z), three electrons (as the number of protons is equal to the number of electrons in an atom), and four neutrons (7 – 3 = 4).
Explanation:
