1
MCQ (Single Correct Answer)

AIPMT 2007

Calculate the pOH of a solution at 25oC that contains 1 $$ \times $$ 10$$-$$10 M of hydronium ions, i.e. H3O+.
A
4.000
B
9.000
C
1.000
D
7.000

Explanation

Given, [H3O+.] = 1 $$ \times $$ 10$$-$$10

$$ \Rightarrow $$ pH = 10

Also we know, pH + pOH = 14

$$ \Rightarrow $$ pOH = 14 - pH = 14 - 10 = 4
2
MCQ (Single Correct Answer)

AIPMT 2007

The equilibrium constants of the following are

N2 + 3H2 $$\rightleftharpoons$$ 2NH3;     K1

N2 + O2 $$\rightleftharpoons$$ 2NO;     K2

H2 + $${1 \over 2}$$O2 $$\rightleftharpoons$$ H2O;     K3

The equilibrium constant (K) of the reaction :

2NH3 + $${5 \over 2}$$ O2 $$\rightleftharpoons$$ 2NO + 3H2O will be
A
K2K33/K1
B
K2K3/K1
C
K23K3/K1
D
K1K33/K2

Explanation

2NH3 $$\rightleftharpoons$$ N2 + 3H2;     $${1 \over {{K_1}}}$$

N2 + O2 $$\rightleftharpoons$$ 2NO;     K2

3H2 + $${3 \over 2}$$O2 $$\rightleftharpoons$$ 3H2O;     (K3)3

By adding all equations, we get

2NH3 + $${5 \over 2}$$ O2 $$\rightleftharpoons$$ 2NO + 3H2O

$$ \therefore $$ K = $${{{K_2} \times {{\left( {{K_3}} \right)}^3}} \over {{K_1}}}$$
3
MCQ (Single Correct Answer)

AIPMT 2006

The hydrogen ion concentration of a 10$$-$$8 M, HCl aqueous solution at 298 K (Kw = 10$$-$$14) is
A
1.0 $$ \times $$ 10$$-$$8 M
B
1.0 $$ \times $$ 10$$-$$6 M
C
1.0525 $$ \times $$ 10$$-$$7 M
D
9.525 $$ \times $$ 10$$-$$8 M

Explanation

In HCl solution [H+] = 10-8 M

Also from water, [H+] = 10-7 M

$$ \therefore $$ Total [H+] = 10-8 M + 10-7 M

= 1.1 ×10–7 M

$$ \simeq $$ 1.0525 $$ \times $$ 10$$-$$7 M
4
MCQ (Single Correct Answer)

AIPMT 2006

Which of the following pairs constitutes a buffer?
A
HCl and KCl
B
HNO2 and NaNO2
C
NaOH and NaCl
D
HNO3 and NH4NO3

Explanation

HNO2 is a weak acid and NaNO2 is its salt thus these two constitute to form an acidic buffer.

EXAM MAP

Joint Entrance Examination

JEE Advanced JEE Main

Medical

NEET

Graduate Aptitude Test in Engineering

GATE CE GATE ECE GATE ME GATE IN GATE EE GATE CSE GATE PI