Answer :
Answer:
The pH of the solution is 1.66
Explanation:
The formula for hydroiodic acid is HI where the atomic mass of hydrogen (H) is 1 g/mol and that of iodine (I) is 127 g/mol.
The formula for pH is
pH = -log[H⁺]
To determine the hydrogen ion concentration, [H⁺], we calculate the molarity of the solution.
The molarity (M) of the solution is
M = number of moles of solute/volume (in dm³ or L)
volume of solution according to the question is 281 mL ⇔ 0.281 L
number of moles of solute (n) = given mass/molar mass
molar mass of HI = 1 + 127 = 128 g
given mass = 781 mg ⇔ 0.781
n = 0.781/128
n = 0.00610
Molarity = 0.00610/0.281
M = 0.0217M
pH = -log0.0217
pH = 1.66
The pH of the solution is 1.66