Click here to download Test-2-Structure of atoms for class – XI

Click here to download Test-2-Solution for class – XII

Class – XII – Solutions , Test Duration – 1:30 min

- Calculate the mass of ascorbic acid (Vitamin C, C
_{6}H_{8}O_{6}) to be dissolved in 75 g of acetic acid to

lower its melting point by 1.5°C. *K _{f}* = 3.9 K kg mol

^{−1}.

2.Calculate the osmotic pressure in pascals exerted by a solution prepared by dissolving 1.0 g of

polymer of molar mass 185,000 in 450 mL of water at 37°C.

- Give an example of solid solution in which the solute is a gas? Explain Henery’s law & is its significance?

**4.**What role does the molecular interaction play in a solution of alcohol and water?

**5.**Why do gases always tend to be less soluble in liquids as the temperature is raised?

- Calculate the depression in the freezing point of water when 10 g of CH
_{3}CH_{2}CHClCOOH is added

to 250 g of water. *K _{a}* = 1.4 × 10

^{−3},

*K*= 1.86 K kg mol

_{f }^{−1}.

- Determine the osmotic pressure of a solution prepared by dissolving 25 mg of K
_{2}SO_{4}in 2 liter of water at

25° C, assuming that it is completely dissociated.

- Based on solute-solvent interactions, arrange the following in order of increasing solubility in

n-octane and explain – Cyclohexane, KCl, CH_{3}OH, CH_{3}CN. cont…..download from link given above .

Class – XI – Structure of Atoms – Duration 1:30 mint.

__1 MARK QUESTION__

- State the physical significance of psi (ψ)?
- Define K-Capture ?
- Which quantum numbers determine the magnetism of an atom?
- Why hockey ball does not seems to made wave?
- How many spectral lines will be obtained when electron jumps from 6
^{th}orbit

to ground state?

- 6. Why electron does not exist in nucleus ?

__2 MARK QUESTION__

- An e
^{–}has a speed of 500 ms^{–}with an uncertainity of 0.02%. What is the

uncertainty in locating its position?

- Show that the circumference of the Bohr orbit for the hydrogen atom is an

integral multiple of the de Broglie wavelength associated with the electron

revolving around the orbit.

__3 MARK QUESTION__

- [a] Write Quantum number in case of Cr ( At. No. 24 ) –
- Highest energu Subshell .
- Outer most electron

[b] The kinetic energy of a sub-atomic particle is 4.55X10-25 J

Calculate the frequency of the particle wave.

- The work function for caesium atom is 1.9 eV. Calculate (a) the threshold

wavelength and (b) the threshold frequency of the radiation. If the caesium

element is irradiated with a wavelength 500 nm, calculate the kinetic energy

and the velocity of the ejected photoelectron.

cont……..download from the link given link.