Solve your IGNOU Doubts

Question:

b) Write the chemical equation and mechanism of pinacol-pinacolone rearrangement.

See Answer →

Question:

a) In normal reaction conditions, chlorobenzene does not react with NaOH, but 1- chloro-4-nitrobenzene reacts with NaOH in these conditions. Explain.

See Answer →

Question:

b) Which one of the following would undergo faster $S_{N^{2}}$ reaction? Explain $CH_{3}-CH=CH-$ or $CH_{3}-CH_{2}CH_{2}-CI$

See Answer →

Question:

a) Explain why Nitro group is meta-directing deactivator?

See Answer →

Question:

b) Write the mechanism of Friedel-Craft’s alkylation. What are its limitations?

See Answer →

Question:

a) List various methods of preparation of benzene and also write one chemical reaction for each case.

See Answer →

Question:

b) Define solubility product constant and derive the relationships between solubility and solubility product constants for salts of AB2, A2B types.

See Answer →

Question:

a) Explain the effect of common ions on the ionisation equilibria of weak acids with the help of a suitable example.

See Answer →

Question:

b) Define degree of ionisation of a weak electrolyte and discuss the factors affecting it.

See Answer →

Question:

a) In the following equilibrium, predict the direction of shift of equilibrium for each condition listed below:

$N_{2}(g) + 3H_{2}(g) \leftrightharpoons 2NH_{3}(g) + 92 kJ$

i) Addition of $H_{2}$

ii) increased pressure

iii) lowering of temperature.

See Answer →

Question:

b) What is reaction quotient and how is it helpful in determining the direction of a given reaction?

See Answer →

Question:

a) Give the statements of Zeroth, First, Second and the Third laws of thermodynamics and outline their significance.

See Answer →

Question:

b) Differentiate between enthalpy driven and entropy driven reactions with the help of suitable examples.

See Answer →

Question:

a) Define standard enthalpy of formation and describe a method for its direct determination with the help of an example.

See Answer →

Question:

a) Define and explain a thermodynamically reversible process.

b) 0.25 mol of an ideal monoatomic gas undergoes isothermal expansion from a volume of 2.0 dm3 to 10 dm3 at 27 oC. Calculate the maximum work that can be obtained from this process.

See Answer →

Question:

e) i) Show that only odd harmonics can be generated in a closed-end organ pipe.

ii) Determine the fundamental frequency and the first 3 overtones of an organ pipe

of length 1.7 m and closed at one end. Take the speed of sound to be 340 $ms^{-1}.$

See Answer →

Question:

d) Standing waves are produced by superposition of the following waves: $y_{1}(x,t)=0.2sin \pi (t-2x)$ and

$y_{2}(x,t)=0.2sin \pi (t+2x)$

(i) Obtain the resultant displacement of the particle at x at time t. (ii) For what value of x will the displacement be zero at all times? (iii) What is the distance between two nearest values of x at which displacements are zero? Is this distance related to the wavelength of the standing wave?

See Answer →

Question:

c) i) The equation of transverse wave on a string is given by $y=5sin \pi (4.0t-0.02x)$

where y and x are in cm and t is in second. Calculate the maximum speed of a particle on the string and wavelength of the wave.

ii) The linear density of a vibrating string is $1.3\times 10^{-4}kg m^{-1}.$ A transverse wave is propagating on the string and is described by the equation: $y(x,t)=0.021$ sin $(x+30t)$

where x and y are in meters and t is in seconds. Calculate the tension in the string.

See Answer →

Question:

a) Calculate the volume of the tetrahedron whose vertices are the points A = (3, 2, 1), B = (1, 2, 4), C = (4, 0, 3) and D = (1, 1, 7).

b) For three vectors $\left ( \vec{u}\times \vec{v} \right )\left [ \left ( \vec{v}\times \vec{w} \right ) \times \left ( \vec{w} \times \vec{u}\right )\right ]=\left [ \vec{u.}\left ( \vec{v}\times \vec{w} \right ) \right ]^{2}.$

See Answer →

Question:

ii) A train moving with speed 72 km $h^{-1}$ emits a whistle of frequency 500 Hz. A person is standing stationary on the platform. Calculate the frequency heard by the person if the train (i) approaches and (ii) recedes away from the listener