Answer:
a. electrophilic aromatic substitution
b. nucleophilic aromatic substitution
c. nucleophilic aromatic substitution
d. electrophilic aromatic substitution
e. nucleophilic aromatic substitution
f. electrophilic aromatic substitution
Explanation:
Electrophilic aromatic substitution is a type of chemical reaction where a hydrogen atom or a functional group that is attached to the aromatic ring is replaced by an electrophile. Electrophilic aromatic substitutions can be classified into five classes: 1-Halogenation: is the replacement of one or more hydrogen (H) atoms in an organic compound by a halogen such as, for example, bromine (bromination), chlorine (chlorination), etc; 2- Nitration: the replacement of H with a nitrate group (NO2); 3-Sulfonation: the replacement of H with a bisulfite (SO3H); 4-Friedel-CraftsAlkylation: the replacement of H with an alkyl group (R), and 5-Friedel-Crafts Acylation: the replacement of H with an acyl group (RCO). For example, the Benzene undergoes electrophilic substitution to produce a wide range of chemical compounds (chlorobenzene, nitrobenzene, benzene sulfonic acid, etc).
A nucleophilic aromatic substitution is a type of chemical reaction where an electron-rich nucleophile displaces a leaving group (for example, a halide on the aromatic ring). There are six types of nucleophilic substitution mechanisms: 1-the SNAr (addition-elimination) mechanism, whose name is due to the Hughes-Ingold symbol ''SN' and a unimolecular mechanism; 2-the SN1 reaction that produces diazonium salts 3-the benzyne mechanism that produce highly reactive species (including benzyne) derived from the aromatic ring by the replacement of two substituents; 4-the free radical SRN1 mechanism where a substituent on the aromatic ring is displaced by a nucleophile with the formation of intermediary free radical species; 5-the ANRORC (Addition of the Nucleophile, Ring Opening, and Ring Closure) mechanism, involved in reactions of metal amide nucleophiles and substituted pyrimidines; and 6-the Vicarious nucleophilic substitution, where a nucleophile displaces an H atom on the aromatic ring but without leaving groups (such as, for example, halogen substituents).
Density is equal to the ratio of mass to the volume.
The mathematical expression is given as:
Density of silver metal bar=
Convert 
into g/L
= 0.001 L
Thus, density = 
= 
Volume = 0.5 L
Put the values,
=
Now, convert gram into kg
1 g = 0.001 kg
Therefore, mass in kg= 
= 5.25 kg
Thus, mass of silver metal bar in kg=5.25 kg
Answer:
Sodium will an electron and chlorine will gain an electron
Explanation:
The electronic configurations of sodium and chlorine are;
Sodium- 1s2 2s2 2p6 3s1
Chlorine- 1s2 2s2 2p6 3s2 3p5
Hence, sodium can easily loose one electron to chlorine to attain a noble gas configuration while chlorine accepts one electron to attain the noble gas configuration.
Double displacement reactions are when the cations and anions of 2 compounds are exchanged. Cation of one reactant will form a new product with the anion of the other reactant and vice versa.
MgCl₂ --> Mg²⁺ + 2Cl⁻
Na₂CO₃ --> 2Na⁺ + CO₃²⁻
the cations and anions are exchanged therefore double displacement reaction is as follows;
MgCl₂(aq) + Na₂CO₃(aq) --> MgCO₃(s) + 2NaCl(aq)
