Calculate [OH-] and pH for each of the following strong base solu...

Question

Calculate [OH-] and pH for each of the following strong base solutions: (a) 0.182 M KOH, (b) 3.165 g of KOH in 500.0 mL of solution, (c) a solution formed by mixing 20.0 mL of 0.015 M Ba(OH)2 with 40.0 mL of 8.2 x 10^-3 M NaOH.

Accepted Answer

For part (a), recognize that KOH is a strong base and dissociates completely in water. The concentration of $$OH^{-}$$ ions is equal to the concentration of KOH. Therefore, [$$OH^{-}$$] = 0.182 M.. To find the pH from the [$$OH^{-}$$], use the relation pOH = -log[$$OH^{-}$$]. Then, use the equation pH + pOH = 14 to find the pH.. For part (b), first calculate the number of moles of KOH using the formula: moles = mass (g) / molar mass (g/mol). The molar mass of KOH is approximately 56.11 g/mol.. Next, calculate the concentration of KOH in the solution by dividing the number of moles by the volume of the solution in liters (0.500 L). This gives you [$$OH^{-}$$].. For part (c), calculate the moles of $$OH^{-}$$ from each solution separately. For Ba(OH)_{2}, remember it dissociates into two $$OH^{-}$$ ions per formula unit. Add the moles of $$OH^{-}$$ from both solutions, then divide by the total volume of the mixed solution in liters to find the final [$$OH^{-}$$]. Use this to calculate pOH and then pH.

Calculate [OH-] and pH for each of the following strong base solutions: (a) 0.182 M KOH, (b) 3.165 g of KOH in 500.0 mL of solution, (c) a solution formed by mixing 20.0 mL of 0.015 M Ba(OH)2 with 40.0 mL of 8.2 x 10^-3 M NaOH.

주요 개념

Strong Bases and Hydroxide Ion Concentration

pH and pOH Relationship

Dilution and Mixing Solutions