In: Chemistry
Part A Calculate [OH−] for 1.20 mL of 0.220 M NaOH diluted to 1.50 L
Part B.Calculate [OH−] for a solution formed by adding 4.60 mL of 0.120 M KOH to 14.0 mL of 8.1×10−2 M Ca(OH)2
Thank you!!
before dilution After dilution
M1 = 0.22M M2 =
V1 = 1.2ml V2 = 1.5L = 1500ml
M1V1 = M2V2
M2 = M1V1/V2
= 0.22*1.2/1500 = 0.000176M
POH = -log[OH-]
= -log0.000176
= 3.7544
PH = 14-POH
= 14-3.7544
= 10.2456
part-B
no of moles of KOH = molarity * volume in L
= 0.12*0.0046 = 0.000552 moles
no of moles of Ca(OH)2 = molarity * volume in L
= 0.081*0.014 = 0.001134 moles
Ca(OH)2 -------------------> Ca^+2(aq) + 2OH^-
0.001134 moles 2*0.001134 moles
Total no of moles of OH^- = 0.000552 + 2*0.001134 = 0.00282 moles
Total volume in L = 0.0046 + 0.014 = 0.0186 L
molarity OH^- = no of moles/volume in L
= 0.00282/0.0186 = 0.1516M