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# NEET Chemistry Solved Question Paper 2011

#### Multiple Choice Questions

1.

One mole of which of the following has the highest entropy ?

• Liquid nitrogen

• Hydrogen gas

• Mercury

• Diamond

B.

Hydrogen gas

Entropy is the measure of degree of disorder (or randomness) of a system . The greater the disorder in a system , the higher is the entropy . Hence , entropy is highest for hydrogen gas .

2.

If the mass defect of ${}_{4}^{0}\mathrm{X}$ is 0.090 u , then binding energy per nucleon is :

(1 u = 931.5 MeV)

• 9.315 MeV

• 931.5 MeV

• 83.0 MeV

• 8.38 MeV

A.

9.315 MeV

$∆$m = 0.090 u

Number of nucleons = 9

$\therefore$ Binding energy per nucleon

= 9.315 MeV

3.

50 mL of 0.1 M HCl and 50 mL of 0.2 M NaOH are mixed .The pH of the resulting solution is :

• 1.30

• 4.2

• 12.70

• 11.70

C.

12.70

50 mL of0.1 M HCl =  = 5 x 10-3

50 mL of 0.2 M NaOH =  = 10 x 10-3

Hence , after neutralisation NaOH left

= 10 x 10-3 - 5 x 10-3 = 5 x 10-3

Total volume = 100 cc

The concentration of NaOH

= 0.05 M

[OH-] = 0.05 M = 5 x 10-2 M

pOH = - log [OH-]

= - log [5 x 10-2]

= 1.3010

pH + pOH = 14

pH = 14 - 1.3010

= 12.699

= 12.70

4.

One mole. of a perfect gas expands isothermally to ten times of its original volume. The change in entropy is :

• 0.1 R

• 2.303 R

• 10.0 R

• 100.0 R

B.

2.303 R

$\mathrm{\Delta }$S = 2.303nR log $\frac{{\mathrm{V}}_{2}}{{\mathrm{V}}_{1}}$

n = 1

$\therefore$ $∆$S = 2.303 R log $\frac{10}{1}$

$∆$S = 2.303R              (log 10 = 1)

5.

100 cc of 0.6 N H2SO4 and 200 cc of 0.3 N HCl were mixed together .The normality of the solution will be :

• 0.2 N

• 0.4 N

• 0.8 N

• 0.6 N

B.

0.4 N

Normality of the mixed solution

$\frac{0.12}{0.3}$ = 0.4 N

6.

1 mole of H2SO4 is mixed with 2 moles of NaOH .The heat evolved will be :

• 57.3 kJ

• 2 x 57.3 kJ

• 57.3/2 kJ

• Cannot be predicted

B.

2 x 57.3 kJ

1 mole of H2SO4 = 2g-equivalent of H2SO4 .Hence , when 1 mole of H2SOis mixed with 2 moles of NaOH , the heat evolved will be 2 x 57.3 kJ .

7.

Conjugate acid of CH3NH2 is :

• CH3OH

• CH3NH3+

• CH2NH2+

• CH3N-H

B.

CH3NH3+

Conjugate acid is obtained , when a base accepts a proton .

$\underset{\mathrm{base}}{{\mathrm{CH}}_{3}{\mathrm{NH}}_{2}}$ + $\underset{\mathrm{proton}}{{\mathrm{H}}^{+}}$ $\to$

8.

For the reaction :

N2 + 3H2 $⇌$ 2NH3$\mathrm{∆}$H = ?

• $∆$E + 2RT

• $∆$E - 2RT

• $∆$E + RT

• $∆$E - RT

B.

$∆$E - 2RT

N2 + 3H2 $⇌$ 2NH3

$∆$H = $∆$E + $∆$ngRT

$∆$ng = np - nr = 2 - 4 = -2

$\therefore$ $∆$H = $∆$E + (-2)RT

$∆$H = $∆$E - 2RT

9.

• its atomic number is high

• it has high $\frac{\mathrm{p}}{\mathrm{n}}$ ratio

• it has high $\frac{\mathrm{n}}{\mathrm{p}}$ ratio

• None of the above

C.

it has high $\frac{\mathrm{n}}{\mathrm{p}}$ ratio

${}_{27}{}^{60}\mathrm{Co}$ is radioactive and unstable due to high $\frac{\mathrm{n}}{\mathrm{p}}$ ratio .

Number of protons = 27

Number of neutrons = 33

$\therefore$ $\frac{\mathrm{n}}{\mathrm{p}}$ for ${}_{27}{}^{60}\mathrm{Co}$ = $\frac{33}{27}$ = 1.22

10.

Amines behave as :

• Lewis acid

• Lewis base

• aprotic acid

• neutral compound

B.

Lewis base

The substance which. can donate a pair of electrons is called Lewis base .

Amines contain a lone pair of electrons on nitrogen atom which is available for donation , so they behave as Lewis base .