Buffer solutions have constant acidity and alkalinity because
1. these give unionised acid or base or base on reaction with added acid or alkali
2. acids and alkalies in these solutions are shielded from attack by other ions
3. they have large excess of H+ or OH- ions
4. they have fixed value of pH

 

Subtopic:  Buffer |
 56%
From NCERT
NEET - 2012
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The molecule that is least likely to behave as Lewis base is: 

1. NH3

2. BF3

3. OH-

4. H2O

Subtopic:  Ionisation Constant of Acid, Base & Salt | Acids & Bases - Definitions & Classification |
 79%
From NCERT
NEET - 2011
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Kc and Kp are not equal for a reaction given below:

1. 2NO(g) N2(g) + O2(g)

2. SO2(g) + NO2(g) SO3(g) + NO(g)

3. H2(g) + I2(g) 2HI(g)

4. 2C(s) + O2(g) 2CO2(g)

Subtopic:  Kp, Kc & Factors Affecting them |
 88%
From NCERT
NEET - 2010
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Which one of the following molecular hydrides acts as a Lewis acid?

1. NH3         

2. H2O         

3. B2H6           

4. CH4

Subtopic:  Acids & Bases - Definitions & Classification |
 79%
From NCERT
NEET - 2010
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Which of the following molecules acts as a Lewis acid ?

1. (CH3)3B

2. (CH3)2O

3. (CH3)3P

4. (CH3)3N

Subtopic:  Acids & Bases - Definitions & Classification |
 82%
From NCERT
NEET - 2009
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The ionisation constant of ammonium hydroxide is 1.77 x 10-5 at 298 K. Hydrolysis constant of ammonium chloride is

1. 5.65 x 10-10

2. 6.50 x 10-12

3. 5.65 x 10-13

4. 5.65 x 10-12

Subtopic:  Kp, Kc & Factors Affecting them | Salt Hydrolysis & Titration |
 73%
NEET - 2009
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The oxide that is not expected to react with sodium hydroxide is : 

1. B2O3           

2. CaO

3. SiO2             

4. BeO

Subtopic:  Acids & Bases - Definitions & Classification |
 58%
From NCERT
NEET - 2009
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The dissociation constants for acetic acid and HCN at 25°C are 1.5 xl0-5 and 4.5 xl0-10,

respectively. The equilibrium constant for the equilibrium,

CN- + CH3COOH  =    HCN + CH3COO-   would be

1. 3.0 x 105

2. 3.0 x 10-5

3. 3.0x10-4

4. 3.0 x 104

Subtopic:  Ionisation Constant of Acid, Base & Salt |
From NCERT
NEET - 2009
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Equal volumes of three acid solutions of pH 3, 4 and 5 are mixed in a vessel. What will be

the H+ ion concentration in the mixture?

1. 1.11 x 10-4 M             

2. 3.7 x 10-4 M

3. 3.7 x 10-3  M             

4. 1.11 x 10-3 M

Subtopic:  pH calculation |
 63%
NEET - 2008
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The value of equilibrium constant of the reaction HI (g)  12 H2(g) + 12 I2(g) is 8.0. The equilibrium constant of the reaction

H2(g) + I2(g) 2HI(g) will be

1. 1162. 1643. 164. 18

Subtopic:  Kp, Kc & Factors Affecting them |
 84%
From NCERT
NEET - 2008
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