At 25 °C, how many dissociated OH− ions are there in 1257 mL of an aqueous solution whose pH is 1.74? number of OH− ions:

Question

At 25 °C, how many dissociated OH− ions are there in 1257 mL of an aqueous solution whose pH is 1.74? number of OH− ions:

Answer 1

pH = 1.74

pOH = 14 - 1.74

pOH = 12.26

[OH^-] = 1x10^-12.26 = 5.50x10^-13 M

1257 ml x 1 L /1000 ml = 1.257 L

1.257 L x 5.50x10^-13 mol/L = 6.9x10^-13 moles OH^-

number of OH^- ions = 6.9x10^-13 mols OH^- x 6.02x10²³ ions / mol of ions = 4.2x10⁹ OH^- ions