Respuesta :
Answer:
C) 0.28 M
Explanation:
Considering:
[tex]Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}[/tex]
[tex]Moles =Molarity \times {Volume\ of\ the\ solution}[/tex]
Potassium hydroxide will furnish hydroxide ions as:
[tex]KOH\rightarrow K^{+}+OH^-[/tex]
Given :
For Potassium hydroxide :
Molarity = 0.25 M
Volume = 40.0 mL
The conversion of mL to L is shown below:
1 mL = 10⁻³ L
Thus, volume = 40.0×10⁻³ L
Thus, moles of hydroxide ions furnished by Potassium hydroxide is same as the moles of Potassium hydroxide as shown below:
[tex]Moles =0.25 \times {40.0\times 10^{-3}}\ moles[/tex]
Moles of hydroxide ions by Potassium hydroxide = 0.01 moles
Barium hydroxide will furnish hydroxide ions as:
[tex]Ba(OH)_2\rightarrow Ba^{2+}+2OH^-[/tex]
Given :
For Barium hydroxide :
Molarity = 0.15 M
Volume = 60.0 mL
The conversion of mL to L is shown below:
1 mL = 10⁻³ L
Thus, volume = 60.0×10⁻³ L
Thus, moles of hydroxide ions furnished by Barium hydroxide is twice the moles of Barium hydroxide as shown below:
[tex]Moles =2\times 0.15 \times {60.0\times 10^{-3}}\ moles[/tex]
Moles of hydroxide ions by Barium hydroxide = 0.018 moles
Total moles = 0.01 moles + 0.018 moles = 0.028 moles
Total volume = 40.0×10⁻³ L + 60.0×10⁻³ L = 100×10⁻³ L
Concentration of hydroxide ions is:
[tex]Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}[/tex]
[tex]Molarity_{OH^-}=\frac{0.028 }{100\times 10^{-3}}[/tex]
The final concentration of hydroxide ion = 0.28 M
Answer:
The molar concentration of OH- is 0.28M (Option C)
Explanation:
Step 1: Data given
Volume of 0.25 M KOH = 40.0 mL = 0.04 L
Volume of 0.15 M Ba(OH)2 = 60.0 mL = 0.06 L
Step 2: Calculate moles of KOH
Moles KOH = Molarity KOH * volume
Moles KOH = 0.25 M * 0.04 L = 0.01 moles
Step 3: Calculate moles of Ba(OH)2
Moles Ba(OH)2 = 0.15 M * 0.06 L
Moles Ba(OH)2 = 0.009 moles
Since We have twice as much OH in Ba(OH)2 as we have in KOH
The quantity of moles in Ba(OH)2 is 0.009 * 2 = 0.018
Step 4: Calculate the total number of moles
The total amount of OH is 0.018 mol + 0.010 mol = 0.028 mol
Step 5: Calculate molarity
Molarity = Number of moles / volume
⇒ with nummber of moles = 0.028 moles
⇒ with volume = 40 + 60 = 100 mL = 0.100 L
The total volume is 100ml = 0.1L
Molarity = 0.028 mol/ 0.1 L = 0.28 M
The molar concentration of OH- is 0.28M
