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NEET Chemistry Solved Question Paper 2012

Multiple Choice Questions

1.

NO2 +$\frac{1}{2}$O2$⇌$NO3 .......K1

2NO2 + O2$⇌$2NO3 ........K2

For the above reaction the relation between equilibrium constant is :

• K2 = (K1)2

• K2$\frac{1}{{\mathrm{K}}_{1}}$

• K2$\frac{1}{{{\mathrm{K}}_{1}}^{2}}$

• K1 = K2

A.

K2 = (K1)2

K1 =$\frac{\left[{\mathrm{NO}}_{3}\right]}{\left[{\mathrm{NO}}_{2}\right]\left[{\mathrm{O}}_{2}{\right]}^{1/2}}$

K2 =$\frac{\left[{\mathrm{NO}}_{3}{\right]}^{2}}{\left[{\mathrm{NO}}_{2}{\right]}^{2}\left[{\mathrm{O}}_{2}\right]}$

so , K2 = (K1)2

2.If the pH of HCl soltion is 2 then the molar concentration of this will be :0.01 M 2 M 0.4 M 0.02 M

A.

0.01 M

pH = - log [H+]

2 = - log [H+]

[H+] = 10-2 = 0.01 M

3.

Fermentation is :

• reversible

• exothermic

• endothermic

• None of these

B.

exothermic

Fermentation is the exothermic process.

4.

The ionisation percentage of 0.2 M HCN the solution is 0.02%. What will be the value of ionisation constant ?

• 8 x 10-5

• 8 x 10-9

• 8 x 10-7

• 8 x 10-3

A.

8 x 10-5

Kh = C$\mathrm{\alpha }$2 = 0.2x (0.02)4

= 0.2 X 0.0004

= 8 x 10-5

5.

The geometry of ammonia is :

• tetrahedral

• pyramidal

• triangular

• trigonal bipyrarnidal

D.

trigonal bipyrarnidal

Hybridisation state in NH3 is sp3 ,But its geometry is trigonal bipyramidal due to the presence of lone pair on N atom .

6.

Which one have the highest melting point ?

• CsCl

• NH3

• He

• CHCl3

A.

CsCl

CsCl is an ionic compound. it has the highest melting point.

7.

Which one act as Bronsted acid as well as Bronsted base?

• Cl-

• OH-

• HCl

• H2O

D.

H2O

H2O is Bronsted acid and base both :

$\underset{\mathrm{Acid}}{{\mathrm{H}}_{2}\mathrm{O}}$+$\underset{\mathrm{Base}}{{\mathrm{H}}_{2}\mathrm{O}}$$⇌$$\underset{\mathrm{Acid}}{{\mathrm{H}}_{3}{\mathrm{O}}^{+}}$+$\underset{\mathrm{Base}}{\mathrm{OH}}$

8.

The value of magnetic quantum number for l = 3 :

• 0 , +1 , +2 , +3

• 0 , ± 1 , ± 2 , ± 3

• -1 , -2 , -3

• ± 1 , ± 2 , ± 3

B.

0 , ± 1 , ± 2 , ± 3

l = 3
m = -3 , - 2 , -1 , 0 , +1 , +2 , +3
or ± 1 , ± 2 , ± 3

9.

BF3 molecule is :

• Lewis base

• Lewis acid

• Neutral

• None of these

B.

Lewis acid

BF3 molecule is Lewis acid.

10.

Number of electron in one molecule of NH3 :

• 17

• 34

• 7

• 10

A.

17

Total number of electron in = NH3
N + H3 = 14 + 3= 17