Answer:
The correct order of increasing reactivity toward nucleophilic acyl substitution is E < D < C < A < F < B.
Explanation:
The stability of the leaving group best determines the manner of reactivity of carboxylates to nucleophilic substitution after the substitution of the nucleophile to the leaving group. The leaving group should, therefore, be protonated with hydrogen ion in the solution to form a stable molecule. From the given list: The leaving group for A, Ethyl thioacetate will be ethanethiol. For B, Acetyl chloride will be Hydrochloric acid. For C, Sodium acetate will be Sodium Hydroxide. For D, Ethyl acetate will be Ethanol. For E, Acetamide will be Ammonia, and for F, Acetic anhydride will be Ethanoic acid. The reactivity of the substitution reaction is dependent on the stability of these leaving groups. The stability of these leaving groups depends on their pKa, and the more the pKa, the lesser the acidity of the leaving group, and the lower the reactivity. Therefore, considering their pKa: A is 8.5, B is -7, C is 13.8, D is 15.9, E is 36, and F is 4.8. When we rearrange this pKa in descending order, we have E, D. C, A, F, B. Which is also the increased reactivity of the nucleophilic acyl substitution.
Answer: Nichrome
Explanation: Hot water system coils are commonly made up of metal alloys which are a combination of two or more elements. The most commonly used metal alloy is “Nichrome”. Nichrome is an alloy of nickel (80%) and chromium (20%).
Answer:
The number of atoms in the outermost shell
Explanation:
For example, the electron shells in the alkali metals contain the following numbers of electrons:
Li: 2, 1
Na: 2, 8, 1
K: 2, 8, 8, 1
They all have one electron in their outermost shell, and they have similar chemical properties.
Carbons starting from the left end:
- sp²
- sp²
- sp²
- sp
- sp
Refer to the sketch attached.
<h3>Explanation</h3>
The hybridization of a carbon atom depends on the number of electron domains that it has.
Each chemical bond counts as one single electron domain. This is the case for all chemical bonds: single, double, or triple. Each lone pair also counts as one electron domain. However, lone pairs are seldom seen on carbon atoms.
Each carbon atom has four valence electrons. It can form up to four chemical bonds. As a result, a carbon atom can have up to four electron domains. It has a minimum of two electron domains, with either two double bonds or one single bond and one triple bond.
- A carbon atom with four electron domains is sp³ hybridized;
- A carbon atom with three electron domains is sp² hybridized;
- A carbon atom with two electron domains is sp hybridized.
Starting from the left end (H₂C=CH-) of the molecule:
- The first carbon has three electron domains: two C-H single bonds and one C=C double bond; It is sp² hybridized.
- The second carbon has three electron domains: one C-H single bond, one C-C single bond, and one C=C double bond; it is sp² hybridized.
- The third carbon has three electron domains: two C-C single bonds and one C=O double bond; it is sp² hybridized.
- The fourth carbon has two electron domains: one C-C single bond and one C≡C triple bond; it is sp hybridized.
- The fifth carbon has two electron domains: one C-H single bond and one C≡C triple bond; it is sp hybridized.
