Answer:
Iodide> Bromide > chloride > flouride
Explanation:
During a nucleophilic substitution reaction, a nucleophilie replaces another in a molecule.
This process may occur via an ionic mechanism (SN1) or via a concerted mechanism (SN2).
In either case, the ease of departure of the leaving group is determined by the nature of the C-X bond. The stronger the C-X bond, the worse the leaving group will be in nucleophilic substitution. The order of strength of C-X bond is F>Cl>Br>I.
Hence, iodine displays the weakest C-X bond strength and it is thus, a very good leaving group in nucleophillic substitution while fluorine displays a very high C-X bond strength hence it is a bad leaving group in nucleophilic substitution.
Therefore, the ease of the use of halide ions as leaving groups follows the trend; Iodide> Bromide > chloride > flouride
Answer:
C) 712 KJ/mol
Explanation:
- ΔH°r = Σ Eb broken - Σ Eb formed
- 1/2Br2(g) + 3/2F2(g) → BrF3(g)
∴ ΔH°r = - 384 KJ/mol
∴ Br2 Eb = 193 KJ/mol
∴ F2 Eb = 154 KJ/mol
⇒ Σ Eb broken = (1/2)(Br-Br) + (3/2)(F-F)
⇒ Σ Eb broken = (1/2)(193 KJ/mol) + (3/2)(154 KJ/mol) = 327.5 KJ/mol
∴ Eb formed: Br-F
⇒ Σ Eb formed (Br-F) = Σ Eb broken - ΔH°r
⇒ Eb (Br-F) = 327.5 KJ/mol - ( - 384 KJ/mol )
⇒ Eb Br-F = 327.5 KJ/mol + 384 KJ/mol = 711.5 KJ/mol ≅ 712 KJ/mol
We first need to convert grams of hydrogen chloride to moles.
molarity = moles of solute/liters of solution
To convert from grams to moles, we need to divide by it's molecular mass.
4.5 g HCl * (1 mole HCl/ 36.46 g HCl) = 0.123 moles HCl
0.12 moles/0.9 L = 0.13 M HCl
If they gave you the volume as 900 mL, then that would be 3 sig figs. And the sig figs would be limited to 2 because the mass.If, however, they gave you the volume as 0.9 L, then that would be 1 sig fig. And the final answer would be limited to to 1 sig fig.
