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Buffer solutions and Henderson equation

55 questions on Buffer solutions and Henderson equation from the Ionic Equilibrium I chapter: 11 NEET level, 22 JEE Main, 22 JEE Advanced. Each one opens with its answer and solution.

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Which of the following mixtures in water acts as an acidic buffer? NEET level
For a basic buffer made of a weak base B and its salt BHCl with a strong acid, the Henderson equation is NEET level
A buffer contains equal concentrations of a weak acid HA and its sodium salt NaA. If pK_a of HA is 4.76, the pH of the buffer is NEET level
A buffer has the maximum buffer capacity when NEET level
An acetic acid - sodium acetate buffer has [CH3COOH] : [CH3COONa] = 1 : 10. Taking pK_a = 4.74, its pH is NEET level
When a small amount of HCl is added to an acetic acid - sodium acetate buffer, the added H+ is mainly consumed by NEET level
Which pair can be used to prepare a basic buffer? NEET level
A weak acid buffer works effectively over the approximate pH range NEET level
An acetic acid - acetate mixture has [acid] : [salt] = 10 : 1. With pK_a = 4.74 the pH is NEET level
A buffer made from a weak acid and its salt is diluted ten times with pure water. According to the Henderson equation (ideal behaviour) its pH NEET level
Which of the following is NOT a buffer solution? NEET level
50 mL of 0.2 M weak acid HA (pK_a = 4.70) is mixed with 50 mL of 0.1 M NaA. Use log 2 = 0.301. The pH of the mixture is JEE Main level
To 1 L of a buffer containing 0.10 M CH3COOH and 0.10 M CH3COONa (pK_a = 4.74), 0.01 mol of solid NaOH is added (no volume change). The new pH is JEE Main level
A solution contains 0.30 M NH3 and 0.15 M NH4Cl. Given pK_b(NH3) = 4.74, log 2 = 0.301 and pK_w = 14, its pH is JEE Main level
For an acetic acid - acetate buffer (pK_a = 4.74), the ratio [CH3COO-]/[CH3COOH] needed for pH = 5.04 is (use log 2 = 0.301) JEE Main level
100 mL of 0.30 M CH3COOH is mixed with 100 mL of 0.10 M NaOH. With pK_a = 4.74 and log 2 = 0.301, the pH is JEE Main level
Sodium acetate (molar mass 82 g/mol) is to be dissolved in 1.0 L of 0.10 M acetic acid so that the pH is pK_a + 0.477 (log 3 = 0.477). The mass of sodium acetat... JEE Main level
To 1 L of buffer containing 0.20 M CH3COOH and 0.20 M CH3COONa (pK_a = 4.74), 0.02 mol HCl gas is added without volume change. The new pH is JEE Main level
A buffer contains 0.10 M HA and 0.20 M NaA. Given K_a(HA) = 1.0 x 10^-5 and log 2 = 0.301, the pH is JEE Main level
A weak acid buffer (pK_a = 4.74) has pH = 4.44. Using log 2 = 0.301, the ratio [salt]:[acid] is JEE Main level
Four buffers all have [acid] = [salt] and the same acid. Which has the highest buffer capacity? JEE Main level
100 mL of a buffer of 0.10 M HA and 0.10 M NaA is diluted to 1.0 L with water. Assuming ideal behaviour, the pH of the diluted solution relative to the original... JEE Main level
60 mL of 0.10 M NH3 is mixed with 20 mL of 0.10 M HCl. Given pK_b = 4.74, log 2 = 0.301, pK_w = 14, the pH is JEE Main level
A buffer contains 0.15 M of a weak acid HA (pK_a = 3.80) and 0.05 M of its sodium salt. Find the pH to two decimal places. JEE Main level
To 500 mL of 0.20 M acetic acid, solid NaOH (molar mass 40 g/mol) is added (no volume change) to obtain pH = pK_a + 0.477 (log 3 = 0.477). Find the mass of NaOH... JEE Main level
To 100 mL of 0.10 M acetic acid, V mL of 0.10 M NaOH is added so that pH = pK_a - 0.301 (log 2 = 0.301). Find V in mL, to one decimal place. JEE Main level
500 mL of a buffer contains 0.20 M HA and 0.20 M NaA. Calculate the decrease in pH (a positive number, two decimals) on adding 0.005 mol of HCl without volume c... JEE Main level
A buffer has 0.09 M acetic acid and 0.20 M sodium acetate. Taking pK_a = 4.74, find its pH to two decimal places. JEE Main level
A solution has 0.25 M NH3 and 0.10 M NH4Cl. Using pK_b = 4.75 and pK_w = 14, find the pH to two decimal places. JEE Main level
Sodium acetate (82 g/mol) is dissolved in 250 mL of 0.40 M acetic acid to make a buffer with pH = pK_a + 0.301 (log 2 = 0.301). Find the mass of sodium acetate ... JEE Main level
A buffer contains 0.30 M of a weak acid HA (K_a = 1.8 x 10^-5) and 0.15 M of NaA. Find [H+] in units of 10^-5 M, to one decimal place. JEE Main level
100 mL of a weak electrolyte solution is mixed with 100 mL of a strong electrolyte solution. Which of the following combinations give a buffer? (Acetic acid and... JEE Main level
A buffer is made with [CH3COOH] = 0.10 M and [CH3COO-] = 0.20 M (pK_a = 4.74, log 2 = 0.301). Select the correct statements. JEE Main level
100 mL of a buffer contains 0.20 M CH3COOH and 0.40 M CH3COONa (pK_a = 4.74). On adding 10 mL of 1.0 M HCl the pH becomes JEE Advanced level
200 mL of 0.10 M NH3 is mixed with 100 mL of 0.10 M HCl, and then 5 mmol of solid NaOH is dissolved in the mixture (no volume change). Given pK_b = 4.74, pK_w =... JEE Advanced level
A solution containing 0.10 M HA and 0.050 M NaA has a measured pH of 4.40 (log 2 = 0.301, 10^-4.40 = 3.98 x 10^-5). Assuming ideal behaviour, K_a of HA is close... JEE Advanced level
What amount of solid NaOH (no volume change) must be added to 1.0 L of 0.20 M weak acid HA (pK_a = 4.74) to make a solution of pH 5.74? JEE Advanced level
100 mL of buffer P (0.20 M HA, 0.10 M NaA) is mixed with 300 mL of buffer Q (0.10 M HA, 0.30 M NaA). With pK_a(HA) = 4.76 and log 2 = 0.301, the pH of the mixtu... JEE Advanced level
500 mL of a buffer contains 0.50 M NH3 and 0.20 M NH4Cl. On bubbling 0.050 mol of HCl gas (no volume change), the pH becomes (given pK_b = 4.74, pK_w = 14) JEE Advanced level
50 mL of 0.20 M weak acid HA (pK_a = 3.90) is mixed with 30 mL of 0.10 M NaOH. The pH of the resulting solution is JEE Advanced level
200 mL of a buffer containing 0.30 M HA and 0.30 M NaA (pK_a = 4.76) is mixed with 50 mL of 0.20 M NaOH. Find the pH to two decimals. JEE Advanced level
200 mL of 0.50 M NH3 (pK_b = 4.74, pK_w = 14) is titrated by adding V mL of 0.50 M HCl until the pH of the solution is 9.00. Find V in mL, to the nearest intege... JEE Advanced level
400 mL of a buffer contains 0.50 M HA and 0.50 M NaA. Find the magnitude of the pH change (two decimals) when 0.020 mol of HCl is added, assuming no volume chan... JEE Advanced level
Solid NH4Cl (53.5 g/mol) is dissolved in 500 mL of 0.20 M NH3 to give a solution of pH 9.00. Given pK_b = 4.74, pK_w = 14 and 10^0.26 = 1.82, find the mass of N... JEE Advanced level
25 mL of 0.10 M weak acid HA is mixed with 10 mL of 0.10 M NaOH. The measured pH is 4.52. Given log 1.5 = 0.176, find pK_a of HA to two decimals. JEE Advanced level
150 mL of 0.20 M HA (K_a = 2.0 x 10^-5) is mixed with 100 mL of 0.10 M NaOH. Using log 2 = 0.301, find the pH to two decimals. JEE Advanced level
1.0 L of a buffer contains 0.20 mol HA and 0.10 mol NaA (pK_a = 4.80, log 2 = 0.301). Select the correct statements (volume changes may be ignored). JEE Advanced level
1.0 L of buffer holds 0.10 mol HA and 0.10 mol NaA (no volume change on additions). Select the correct statements. JEE Advanced level
A solution contains 0.40 M NH3 and 0.20 M NH4Cl (pK_b = 4.74, pK_w = 14, log 2 = 0.301). Select the correct statements. JEE Advanced level
Each of the following solutions is prepared from a weak acid HA (pK_a = 4.80) in water. For which does pH = 4.80? (Assume ideal behaviour.) JEE Advanced level
A buffer of pH 5.0 is needed. Four weak acids have pK_a values: HA1 3.2, HA2 4.1, HA3 5.4, HA4 7.0. Using the rule that a buffer works well when |pH - pK_a| le ... JEE Advanced level
A weak acid buffer has pK_a = 4.74 and pH = 5.04 (log 2 = 0.301). Select the correct statements. JEE Advanced level
Buffer X: 0.50 M HA + 0.50 M NaA. Buffer Y: 0.05 M HA + 0.05 M NaA. Same acid (pK_a = 4.74). To 1.0 L of each, 0.02 mol NaOH is added (no volume change). Select... JEE Advanced level
For a buffer made from 0.30 mol HA and 0.60 mol NaA in 1.0 L (pK_a = 4.74, log 2 = 0.301), select the correct statements. JEE Advanced level
HA has K_a = 1.0x10^-5. Which mixtures give pH = 5.30? Use log 2 = 0.301 and take pH = pK_a + log(salt/acid). JEE Advanced level