physical chemistry

PHYSICAL CHEMISTRY
CLASS XII
TIME : 3 HRS M.M. 70
General Instructions :
All questions are compulsory
Ques No. from 1 to 8 carry 1 marks, 9 – 18 carry 2 marks, 19 – 27 carry 3 marks, 28-30 carry 5 marks
Use log table if necessary.
1. Name a salt that can be added to Agcl so as to produce Cation Vacancy.
What is the difference between phosphorus doped and gallium doped semiconductors.
Which one will have a higher boiling point out of 0.1 m sucrose solution and 0.1 m Kcl solution.
Name two material other than hydrogen that can be used as fuels cells.
State Hardy Schubye Rule.
What are the hydrolysis product of lactose.
Why does phyxcarption decrease with the increase of temperature.
Write the relationship between E0 of cell and equilibrium constant K.
Gold (atomic radius = 0.144nm) crystallize in a fee unit cell. What is the length of a side of the unit cell.
The vapour pressure of Water is 12.3 KPa at 300 K. Calculate the vapour pressure of one molal solution containing a solute in it.
A solution is prepared by dissolving 8 gm of BaCl2 in 100 gm of water raises the boiling point of water by 0.52 K. Calculate the % di______ of BaCl2; Kb for Water = 0.52 kg mol-1.
(a) Why are substance like platinum and Polladium often used for carrying out electrlysis of aqueous solutions.
(b). What is the role of desorption in the process of catalysis.
13. The same quantity of electric charge deposited 0.583 g of Ag when passed through AgNo3, Aucl3 solution. Calculate the weight of gold formed.
14. Define Poeudofirst order reaction. Give two examples.
15. (a) What are hormones. Give an example.
(b) Why are hormones called chemical messengers.
16. What is the difference between nucleoside and nucleotides.
17. The rate for the decomposition of NH3 on Platinum surface is zero order. What is the rate of production of N2 and H2 if
K = 2.5 Alo-4 MS-1
18. What are the essential and non essential amino acid. Give two examples of each.
19. Pure silicon is an insulator. Silicon doped with phosphorus is a semiconductor.
Silicon doped with gallium is also a semiconductor. What is the difference between the two semiconductors?
20. (a). Define Corrosion.
(b). Describe the electrochemical phenomenon of rusting of iron.
(c ). Why does CO2 increases rate of corrosion.
21. How are Au, Pt and Ag sol prepared.
22. What type of bonding occurs in :
(a) L – helix configuration
(b) Globular proteins
(c ) B Sheet Structure
23. In a crystalline solid anions, C are arranged in CCP cations. A occupy 50% of the octahedral voids. What is the formula of the solid?
24. A mixture of ethanol and acetone shows positive deviation from ideal behavior whereas that of chloroform and acetone shows negative deviation. Explain.
25. (a) The E0 value at 293 K corresponding to the following true radiation electrode potential are
(i) cu + / cu = + 0.52 V
(ii) cu2+ / cu+ = +0.16 V















Formulate the galvanic cell for their combination. What will be the cell potential?
(b) Calculate rG0 for the cell reaction (IF = 96500 C mol1)
26. The rate of a particular reaction triples when temperature from 500C to 1000 C. Calculate the activation energy of the reaction
( log 3 = 0.4771; R = 8.314 JK-1 mol-1)
27. (a) What are lyophitic and lyophobic sols. Give one example of each type.
(b) Which one of theses two types of sols is easily cogitated and why.
28. (a) At 3000 C the thermal decomposition of H1(g) is found to be 20%. What will be the equilibrium concentration of H2(g) and J2(g) in the system.
H2(g) + J2(g) 2HI(g) at this temp if the equilibrium concentration of HI in it be 0.96 molL-1.
(b) Answer the following questions on the basis of the given curve for the first order reaction.
A P
What is the relationship between slope of this line and rate constant.
(ii) Calculate the rate constant of the above reaction if the slope is 2 X 10-4 S-1
(c ). Derive the relationship between the half life of a first order reaction and rate constant.
Log (R0)
(R)


time
OR
Hydrogen peroxide, H2O2(aq) decomposes to H2O2 and O2(g) in a reaction that is of first order in H2O2 and has a rate constant K = 1.06 X 10-3min-1
How long will it take 15% of a sample of H2O2 to decompose.
How long will it take 85% of a sample of H2O2 to decompose.
29. (a) Explain why electrolysis of aqueous solution of Nacl gives H2 at cathode and cl2 at anode.
Write overall reaction.
(E0Na+/ Na = + 1.36 V, E0H20/H2 = - 0.83V)
(E0cl2pcl- = + 1.36V, E0H+ + O2 / H2O = 1.23 V)
(b) Calculate the emf of the cell
Zn/ Zn21 (0.1M) col4 (0.01) / cal at 298 K
( Given E0 Zn2+ / Zn = - 0.76 V and
E0 cla2+/ cd = - 0.40V)
OR
What are fuel cell, How do they resemble and differ from galvanic cell.
Conductivity of 0.00241 M acetic acid is 7.896 X 10-5 S cm-1. Calculate its molar conductivity. If m for acetic acid is 390.55cm2 mol-1. What is its dissociation constant.
30. (i) 45 gm of ethylene glycol ( C2H6O2) is mixed with 600gm of water
(a) freezing point depression
(b) freezing point of the solution
Explain why freezing point of water is lowered on dissolving Nacl in H2O.
(iii) Give one important application of the phenomenon of depression in freezing point.
OR
State Henry’s law and mention one of its important applications.
Determine the amount of CaCl2 ( I – 247) dissolved in 2.5 litre of water so that its osmotic pressure is 0.75 atm. At 270C.