When the reaction equation is:
HF ↔ H+ + F-
and when the Ka expression
= concentration of products/concentration of reactions
so, Ka = [H+][F-]/[HF]
when we assume:
[H+] = [F-] = X
and [HF] = 0.35 - X
So, by substitution:
6.8 x 10^-4 = X^2 / (0.35 - X) by solving for X
∴ X = 0.015 M
∴[H+] = X = 0.015
when PH = -㏒[H+]
∴PH = -㏒0.015
= 1.8
To calculate the mass of milk of magnesia given, we need certain data like molar mass of the compound which needs the atomic mass of the atoms in the compound. We calculate as follows:
Molar mass of <span>Mg(OH)2 = 24.3 g/mol + (2 x (16 + 1.0)) = 58.30 g/mol
Mass = 3.2 mol (</span>58.30 g/mol) = 186.56 grams
The answer is A. As the first statement is a true statement. Hope this help you
