In: Chemistry
Calculate the pH of a 365.8-mL sample of 0.007 M Ba(OH)2 solution. Assume complete dissociation. Provide your answer to two decimal places and without units.
Ba(OH)2 ---> Ba+2 + 2(OH)-
0.007 M 0.007 M 0.014 M
Given,
Volume of sample = 365.8 ml
So the concentration of OH- ions = 0.014 * 365.8 / 1000
= 5.1212 * 10-3 M
Since,
pH = 14 – pOH ---(1)
pOH = -log( [OH-] ) ---(2)
so putting the value in equation 2 and then in equation 1
pOH = -log( 5.1212 * 10-3 )
pOH = 3 – log ( 5.1212 )
pOH = 3 – 0.7093
pOH = 2.2906
and now by equation 1
pH = 14 – pOH
pH = 14 – 2.2906
pH = 11.70 (this is the required answer )