Find the pH (initial pH –final pH) when 100 ml 0.01 M HCl is added in a solution containig 0.1 m molesof NaHCO3 solution (pH = 9 ) of negligible volume ( Kai =10–7, Ka, =10–11 for H2CO3) :

(1) 6 + 2 log3

(2) 6 – log3

(3) 6 + 2 Log2

(4) 6 – 2 log3

Subtopic:  pH calculation |
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh
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NEET 2023 - Target Batch - Aryan Raj Singh

The ionization constant of benzoic acid is 6.46 x 10–5 and Kc for silver benzoate is 2.5 x 10–13. How many times silver benzoate is more soluble in a buffer of pH = 3.19 as compared to its solubility in pure water ?

(1) 3.317

(2) 9.5

(3) 1000

(4) 7.5

Subtopic:  Introduction To Equilibrium |
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30 ml of 0.06 M solution of the protonated form of an anion acid methionine (H2A+) is treated with 0.09 M NaOH. Calculate pH after addition of 20 ml of base. pKa1, = 2.28 and pKa2 = 9.2.

1. 5.5

2. 5.74

3. 9.5

4. None

Subtopic:  pH calculation |
 70%
From NCERT
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A certain acid–base indicator is red in acid solution and blue in basic solution 75% of the indicator is presentin the solution in its blue form at pH = 5. Calculate the pH at which the indicator shows 90% red form?

(1) 3.56

(2) 5.47

(3) 2.5

(4) 7.4

Subtopic:  Salt Hydrolysis & Titration |
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Ionisation constant of HA (weak acid) and BOH (weak base) are 3.0 x 10–7 each at 298K. The percent degree of hydrolysis of BA at the dilution of 10L is :

1. 25

2. 50

3. 75

4. 40

Subtopic:  Salt Hydrolysis & Titration |
 51%
From NCERT
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Calculate the molar solubility of zinc tetrathiocyanato–N–mercurate (II) if its Ksp = 2.2 x 10–7.

(1) 0.00380

(2) 0.000469

(3) 0.0095

(4) 0.0183

Subtopic:  Solubility Product |
 72%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh

An acid–base indicator which is a weak acid has a pKa value = 5.45. At what cocentration ratio of sodiumacetate to acetic acid would the indicator show a colour half–way between those of its acid and conjugate base forms? pKa of acetic acid = 4.75. [log 2 = 0.3]

(1) 4 : 1

(2) 7 : 1

(3) 5 : 1

(4) 2 : 1

Subtopic:  Buffer |
From NCERT
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The indicator constant of phenolphthalein is approximately 10–10. A solution is prepared by adding 100.01c.c. of 0.01 N sodium hydroxide to 100.00 c.c. of 0.01N hydrochloric acid. If a few drops of phenolphthalein are now added, what fraction of the indicator is converted to its coloured form?

(1) 23

(2) 34

(3) 12

(4) 911

Subtopic:  Ionisation Constant of Acid, Base & Salt |
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A certain mixture of HCl and CH3 – COOH is 0.1 M in each of the acids. 20 ml of this solution is titrated against 0.1M NaOH. By how many units does the pH change from the start to the stage when the HCl is almost completely neutralised? Ka for acetic acid = 1.8 x 10–6.

(1) 2.03

(2) 0.775

(3) 2.325

(4) 3.172

Subtopic:  pH calculation |
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A buffer solution is made by mixing a weak acid HA (Ka = 10–6) with its salt NaA in equal amounts. What should be the amount of acid or salt that should be added to make 90 ml of buffer solution of buffer capacity. 0.1 ?

(1) 10 milli moles

(2) 22 milli moles

(3) 9 milli moles

(4) 11 milli moles

Subtopic:  Buffer |
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NEET 2023 - Target Batch - Aryan Raj Singh
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