Answer: 13
Explanation:
First, we need to find the number of mole of 716.mg of KOH
Molar Mass of KOH = 39 + 16 +1 = 56g/mol
Mass conc. of KOH = 716.mg
Converting from mg to g,we have
716/1000 = 0.716g
Number of mole = Mass conc. /MM
= 0.716/56 = 0.0128mol
Next, we find the number of mole of KOH in 1L of the solution
0.0128mol of KOH dissolves in 130mL(i.e 0.13L) of solution
Therefore, Xmol of KOH will dissolve in 1L of the solution i.e
Xmol of KOH = (0.0128)/0.13
= 0.098mol/L
Next, we find the [OH^-]
KOH <==> K^+ + OH^-
[KOH] =0.098mol/L
[K^+] = 0.098mol/L
[OH^-] = 0.098mol/L
Next, we find the pOH
pOH= -log [OH^-]
pOH = - log 0.098
pOH = 1
Recall
pH + pOH = 14
pH = 14 — pOH
pH = 14 — 1
pH = 13
Th the pH of the solution is 13.
