Answer:
5.7
Explanation:
(C₂H₅)₃NHCl dissociates according to the following equation.
(C₂H₅)₃NHCl ⇒ (C₂H₅)₃NH⁺ + Cl⁻
The molar ratio of (C₂H₅)₃NHCl to (C₂H₅)₃NH⁺ is 1:1. Then, the concentration of (C₂H₅)₃NH⁺ is Ca = 0.166 M.
(C₂H₅)₃NH⁺ is the conjugate acid of (C₂H₅)₃N. Given the Kb of (C₂H₅)₃N, we can calculate Ka for (C₂H₅)₃NH⁺ using the following expression.
Ka × Kb = Kw
Ka = Kw / Kb
Ka = 1.0 × 10⁻¹⁴ / 5.2 × 10⁻⁴
Ka = 1.9 × 10⁻¹¹
(C₂H₅)₃NH⁺ dissociates according to the following equation.
(C₂H₅)₃NH⁺ ⇄ (C₂H₅)₃N + H⁺
We can calculate [H⁺] using the following expression.
[H⁺] = √(Ca × Ka) = √(0.166 × 1.9 × 10⁻¹¹) = 1.8 × 10⁻⁶
The pH is:
pH = -log [H⁺] = -log 1.8 × 10⁻⁶ = 5.7
1. First, move the decimal place until you have a number between 1 and 10. If you keep moving the decimal point to the right in 0.0000073 you will get 7.3.
2. Next, count how many places you moved the decimal point.
Iodine 131 and iodine 126 are the same in the sense that, they both have the same number of electrons and protons in their atoms, it is only the number of their neutrons that is different. Iodine 131 has 78 neutrons while iodine 126 has 73 neutrons.
