Question

In: Chemistry

Part B What is the pH after 0.150 mol of HCl is added to the buffer...

Part B

What is the pH after 0.150 mol of HCl is added to the buffer from Part A? Assume no volume change on the addition of the acid.

Express the pH numerically to three decimal places.

Part A What is the pH of a buffer prepared by adding 0.809 mol of the weak acid HA to 0.507 mol of NaA in 2.00 L of solution? The dissociation constant K a of HA is 5.66× 10 −7 . Express the pH numerically to three decimal places

Expert Solution

PART A

First we need to calculate molar concentrations of weak acid & its salt.

We have, [ HA ] = No. of moles of HA / volume of solution in L

[ HA ] = 0.809 mol / 2.00 L = 0.4045 M

[ NaA ] = 0.507 mol / 2.00 L = 0.2535 M

pH of buffer solution is calculated by using Henderson's equation.

pH = pKa + log [ NaA ] / [ HA ]

pH = - log Ka + log [ NaA ] / [ HA ]

pH = - log ( 5.66 10 ^-07 ) + log 0.2535 / 0.4045

pH = 6.247 + log 0.2535 / 0.4045

pH = 6.247 - 0.2029

pH = 6.044

PART B

Consider reaction of HCl with buffer solution.

When HCl is added to buffer solution. It reacts with basic component of buffer solution . In this case, HCl reacts with NaA & produces HA. Therefore, concentration of HA increases & that of NaA decreases.

NaA + HCl HA + NaCl

Let's use ICE table.

Concentration ( moles )	NaA	HCl	HA
I	0.507	0.150	0.809
C	- 0.150	-0.150	+0.150
E	0.357	0.000	0.959

pH of buffer solution after addition of HCl is calculated by using equation pH = pKa + log [ NaA ] / [ HA ]

pH = 6.247 + log ( 0.357 mol / 2.00 L ) / ( 0.959 mol / 2.00 L )

pH = 6.247 - 0.4292

pH = 5.818

ANSWER : pH buffer solution after addition of HCl is 5.818

queen_honey_blossom answered 2 years ago

Calculate the pH if 0.03 mol HCl is added to 0.500 L of a buffer solution...

Calculate the pH if 0.03 mol HCl is added to 0.500 L of a buffer solution that is 0.24 M NH3 and 0.20 M NH4Cl? For NH3 Kb= 1.8 x 10-5

Determine the pH change when 0.093 mol HCl is added to 1.00 L of a buffer...

Determine the pH change when 0.093 mol HCl is added to 1.00 L of a buffer solution that is 0.497 M in HNO2 and 0.311 M in NO2-. pH after addition − pH before addition = pH change = ___________________ Determine the pH change when 0.115 mol KOH is added to 1.00 L of a buffer solution that is 0.457 M in HNO2 and 0.256 M in NO2-. pH after addition − pH before addition = pH change =_____________

Part A: What is the pH of a buffer prepared by adding 0.405 mol of the...

Part A: What is the pH of a buffer prepared by adding 0.405 mol of the weak acid HA to 0.608 mol of NaA in 2.00 L of solution? The dissociation constant Ka of HA is 5.66×10−7. Part B: What is the pH after 0.150 mol of HCl is added to the buffer from Part A? Assume no volume change on the addition of the acid. Part C: What is the pH after 0.195 mol of NaOH is added to...

PART A: What is the pH of a buffer prepared by adding 0.506 mol of the...

PART A: What is the pH of a buffer prepared by adding 0.506 mol of the weak acid HA to 0.305 mol of NaA in 2.00 L of solution? The dissociation constant Ka of HA is 5.66×10−7? PART B: What is the pH after 0.150 mol of HCl is added to the buffer from Part A? Assume no volume change on the addition of the acid. Express the pH numerically to three decimal places. PART C: What is the pH...

Part A What is the pH of a buffer prepared by adding 0.607 mol of the...

Part A What is the pH of a buffer prepared by adding 0.607 mol of the weak acid HA to 0.406 mol of NaA in 2.00 L of solution? The dissociation constant Ka of HA is 5.66×10−7. Express the pH numerically to three decimal places. Answer: pH = 6.072 Part C What is the pH after 0.195 mol of NaOH is added to the buffer from Part A? Assume no volume change on the addition of the base. Express the...

0.2 mol of gaseous HCl is added to 1.0 L of a buffer solution that contains...

0.2 mol of gaseous HCl is added to 1.0 L of a buffer solution that contains 3.0 M CH3COOH and 3.0 M CH3COONa. What is the pH of the solution? Assume that Ka for CH3COOH is 10-5. Assume also that the volume of the solution does not change when the HCl is added. Type your answer in decimal number carrying only one digit after decimal. So you must round up or down at the second digit after decimal. For example,...

if 0.050 mol of hcl is added to 1.0 l of buffer solution containing 0.125 M...

if 0.050 mol of hcl is added to 1.0 l of buffer solution containing 0.125 M potassium acetate and 0.10 M acetic acid what is the change in PH of the solution

Calculate the change in pH that occurs when 0.00100 mol of gaseous HCl is added to...

Calculate the change in pH that occurs when 0.00100 mol of gaseous HCl is added to a buffer solution that is prepared by dissolving: A) 4.92g of sodium acetate (molar mass = 82.03g/mol) in 250 mL of 0.150 mol/L of acetic acid solution? B) 0.492g of sodium acetate (molar mass = 82.03g/mol) in 250 mL of 0.0150 mol/L of acetic acid solution? Assume no change in volume upon addition of either the sodium acetate or HCl. (Ka for acetic acid...

calculate the change in pH that occurs when 0.00100 mol of gaseous HCL is added to...

calculate the change in pH that occurs when 0.00100 mol of gaseous HCL is added to a buffer solution that is prepared by dissolving 4.92 g of sodium acetate in 250 ml of 0.150 mol L^-1 of acetic acid solution? Assume no change in volume upon addition of either sodium acetate of HCL (Ka=1.8x10^-5)

Determine the pH change when 0.089 mol KOH is added to 1.00 L of a buffer...

Determine the pH change when 0.089 mol KOH is added to 1.00 L of a buffer solution that is 0.343 M in HCN and 0.386 M in CN-. pH after addition − pH before addition = pH change =