Respuesta :
Explanation:
The chemical reaction equation will be as follows.
[tex]H_{3}PO_{4} + 3NaOH \rightarrow Na_{3}PO_{4} + 3H_{2}O[/tex]
In this reaction, 1 mole of [tex]H_{3}PO_{4}[/tex] reacts with 3 mole NaOH. So, the number of moles of [tex]H_{3}PO_{4}[/tex] present in 150 ml of 0.1 M solution is calculated as follows.
No. of moles = [tex]\frac{150}{1000 \times 0.1}[/tex]
= 0.015 mol
As it reacts with 3 moles of NaOH. Hence, no.. of moles of NaOH are:
[tex]3 \times 0.015 mol[/tex]
= 0.045 mol
So, moles of NaOH in 400 of 0.2 M NaH is as follows.
No. of moles = [tex]\frac{400}{1000 \times 2}[/tex]
= 0.080 mol
Hence, no. of moles remained after the reaction are as follows.
(0.080 - 0.045) mol
= 0.035 mol NaOH in 550 ml (400 ml + 150 ml)
As molarity is the no. of moles present in liter of solution. Hence, molarity of NaOH is as follows.
Molarity = [tex]\frac{\text{no. of moles}}{\text{volume in liter}}[/tex]
= [tex]\frac{0.035}{550}[/tex]
= 0.0636 M
As, [tex][OH^{-}][/tex] = 0.0636 M. Hence, pOH will be 1.20.
As, pH + pOH = 14
pH = 14 - pOH
= 14 - 1.20
= 12.80
Also, [tex][H^{+}] = 10^{-pH}[/tex]
So, [tex][H^{+}] = 10^{-12.80}[/tex]
= [tex]1.58 \times 10^{-13}[/tex] M
Thus, we can conclude that pH of the given solution is 12.80 and its hydrogen ion concentration is [tex]1.58 \times 10^{-13}[/tex] M.
Answer:
pH = 12.80
[H+] = 1.58 * 10^-13 M
Explanation:
Step 1: Data given
Volume of 0.2M NaOH = 400 mL
Volume of 0.1M H3PO4 = 150 mL
Step 2: The balanced equation
H3PO4 + 3NaOH → Na3PO4 + 3H2O
For 1 mol H3PO4 we need 3 mol of NaOH to produce 1 mol Na3PO4 and 3 mol H2O
Step 3: Calculate moles H3PO4
Moles H3PO4 = molarity * volume
Moles H3PO4 = 0.1 M * 0.150 L
Moles H3PO4 = 0.015 moles
Step 4: Calculate moles NaOH
Moles NaOH = 0.2M * 0.400 L
Moles NaOH = 0.08 moles
For 1 mol H3PO4 we need 3 mol of NaOH to produce 1 mol Na3PO4 and 3 mol H2O
0.015 mol H3PO4 will react with 0.045 mol NaOH
Step 5: Calculate moles remaining
H3PO4 will be completely consumed
There will remain 0.08 - 0.045 = 0.035 moles of NaOH
Step 6: Calculate total volume
Total volume = 400 mL + 150 mL = 550 mL = 0.550 L
Step 7: Calculate molarity of the solution
Molarity = moles / volume
Molarity = 0.035 moles / 0.550 L
Molarity = 0.0636 M NaOH
Step 8: Calculate pOH
[OH-] = 0.0636M
pOH = -log [OH-]
pOH = -log(0.0636)
pOH= 1.20
Step 9: Calculate pH
pH = 14.00- pOH
pH = 14.00 - 1.20
pH = 12.80
[H+] = 10^-12.80
[H+] = 1.58 * 10^-13 M
