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# NEET Chemistry Solved Question Paper 2009

#### Multiple Choice Questions

1.

The equilibrium constant (K) of a reaction may be written as

B.

2.

For the Paschen series the values of n1 and nin the expression

• n1= 1, n2 = 2, 3, 4, ...

• n1= 2, n2 = 3, 4, 5,...

• n1= 3, n= 4,5,6,...

• n1= 4, n2 = 5,6,7,...

C.

n1= 3, n= 4,5,6,...

Paschen series is the third series of hydrogen spectrum and lies in the infrared region, therefore for this series, n1 = 3 and n> n1,ie, 4, 5, 6,....

# 3.Which of the following will decrease the pH of  a 50 mL solution of 0.01 M HCl?Addition of 5 mL of 1 M HCl Addition of 50 mL of 0.01 M HCl Addition of 50 mL of 0.002 M HCl Addition of Mg

B.

Addition of 50 mL of 0.01 M HCl

Millimoles of 50 mL of 0.01 M HCl
= 50 x 0.01 M = 0.5
pH of the solution =-log (0.5) = 0.3010

(a) On adding 5 mL of 1 M HCl,
Concentration of the resultant solution

=

:. pH of the solution = -log (0.1) = 1

(b) On adding 50 mL or 0.01 M HCl,
Concentration of the resultant solution

=

:. pH of the solution = -log (0.01) = 2

(c) On adding 50 mL of 0.002 M HCl,
concentration of the resultant solution

=

:. pH of the solution = -log (6 x 10-3)= 2.22

4.

• -1

• $-\frac{1}{2}$

• $\frac{1}{2}$

• 1

B.

$-\frac{1}{2}$

5.

The second law of thermodynamic says that in a cyclic process

• work cannot be converted into heat

• heat cannot be converted into work

• work cannot be completely converted into heat

• heat cannot be completely converted into work

D.

heat cannot be completely converted into work

Second law of thermodynamics states that in a cyclic process heat cannot be converted completely into work because attainment of 0 K temperature is impossible.

6.

Under which of the following conditions is the relation  valid for a closed system ?

• Constant pressure

• Constant temperature

• Constant temperature and pressure

• Constant temperature, pressure and composition

A.

Constant pressure

At constant pressure,

7.

Hybridisation of central atom in NF3 is

• sp3

• sp

• sp2

• dsp2

A.

sp3

Number of hybrid orbitals = number of $\mathrm{\sigma }$ bonds + number of lone pairs

$⇒3\mathrm{\sigma }$ bonds + 1 lone pair = 4

.:. Hybridisation of N is sp3 and geometry of the molecule is pyramidal.

8.

Equal volumes of molar hydrochloric acid 'and sulphuric acid are neutralized by dilute NaOH solution and x kcal and y kcal of heat are liberated respectively. Which of the following is true ?

• x = y

• x =y/2

• x = 2y

• none of these

B.

x =y/2

Heat of neutralisation= Heat of formation of water (1 mol).

9.

1 mole of photon, each of frequency 2500 s-1, would have approximately a total energy of

• 10 erg

• 1 J

• 1 eV

• 1 MeV

A.

10 erg

Frequency of one photon = 2500 s-1
:. Frequency of 1 mole of photon
= 6.023 x 1023 x 2500 s-1

10.

An organic compound made of C, H and N contains 20% nitrogen. Its molecular weight is

• 70

• 140

• 100

• 65

A.

70

Atomic mass of nitrogen= 14
Since the compound contains C, H and N, at
least one N atom must be there in the molecule.

:. The minimum molecular weight of the organic  compound = 70.