﻿ The solubility product of Mg(OH)2 at 25°C is 1.4 x 10-11

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## NEET Chemistry Solved Question Paper 2007

#### Multiple Choice Questions

1.

What is the frequency of a X-ray photon whose momentum is 1.1 x 10-23 kg-ms-2 ?

• 5 x 1016 Hz

• 0.5 x 1027 Hz

• 0.5 x 1018 Hz

• 5 x 1018 Hz

2.

The magnitude of orbital angular momentum of an electron of azimuthal quantum number 2 is :

• $\frac{2\mathrm{h}}{2\mathrm{\pi }}$

• $\frac{\sqrt{6}\mathrm{h}}{2\mathrm{\pi }}$

• $\frac{\sqrt{2}\mathrm{h}}{2\mathrm{\pi }}$

• $\frac{6\mathrm{h}}{2\mathrm{\pi }}$

3.

The pH of a 0.02 M solution of HCl is :

• 2.2

• 2.0

• 0.3

• 1.7

# 4.The solubility product of Mg(OH)2 at 25°C is 1.4 x 10-11 .What is the solubility of Mg(OH)2 in g/L ?0.0047 g/L 0.047 g/L 0.0087 g/L 0.087 g/L

C.

0.0087 g/L

Mg(OH)2 $⇌$ Mg2+ + 2OH-

Ksp = [Mg2+][OH-]2

1.4 X 10-11 = (s)(2s)2

1.4 X 10-11 = 4s3

s = 1.5 x 10-4 mol/L

($\because$Mol. wt. of Mg(OH)2 = 52)

= 58 X 1.5 x 10-4

= 0.0087 g/L

5.

The heat of formarion of CO2 is - 393 kJ mol-1 .The amount of heat evolved in the formation of 0.156 kg of CO2 .

• - 1393 kJ

• + 1165.5 kJ

• + 1275.9 kJ

• - 1165.5 kJ

6.

The geometry of methane molecule is :

• tetrahedral

• pyramidal

• octahedral

• square planar

7.

Heisenberg's uncertainty principle can be explained as :

• $∆$$⩾$

• $\mathrm{∆}$x x $∆$$⩾$ $\frac{\mathrm{h}}{4\mathrm{\pi }}$

• $∆$x x $∆$$⩾$ $\frac{\mathrm{h}}{\mathrm{\pi }}$

• $∆$$⩾$ $\frac{\mathrm{\pi h}}{∆\mathrm{x}}$

8.

The bond energy is the energy required to :

• dissociate one mole of the substance

• dissociate bond in 1 kg of the substance

• break one mole of similar bonds

• break bonds in one mole of the substance

9.

Heat of neutralisation of an acid with a base is 13. 7 kcal when :

• both acid and base are weak

• acid is weak and base is strong

• both acid and base are strong

• acid is strong and base is weak

10.

Hess's law is based on :

• law of conservation of mass

• law of conservation of energy

• enthalpy is a state function

• none of the above