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.

sure shot of inorganicl chemistry

INORGANIC 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.
Why should not medicines be taken without consulting doctors.
Give one example of hexadentate ligand. Give its use.
Name the chemicals responsible for the antiseptic properties of dettol.
Why are cr2+ of reducing and Mn3+ oxidising when both have d4 configuration.
Give balanced equations for preparation of K2Cr2O7 from Chromatic ore.
How does Ammonia react with a solution of cu2+.
Why does Pcl3 fume in moisture.
Why do transition metal ions have high enthalpy of hydration.
Why do noble gases have comparatively large atomic sizes.
Mention one important use of each of the following :
a) Equanil b) Sucralose
11. Why tetrahedral complexes not show geometrical isomerism but show optical isomerism.
OR
[Fe(CN)6]4- and [Fe(H2O)6]2+ are of different colours in dilute solution. Why?
Why do actinides in general exhibit a greater range of oxidation states, than the lthanoides.
Write the balanced equations for the following reactions :
a) P4 + KOH + H2O
b) SF4 + H2O
Name two poisonous gases which can be prepared from chlorine gas.
a) Name the method used for refining of
i) Nickel ii) Zircoium
b) The extraction of Au by leaching with NaCN involves both oxidation and reduction. Justify.
16. Why Fluorine is a stronger oxidising agent than chlorine.
17. Why is the reduction of a metal oxide easier if the metal formed is in liquid state at the temperature of reduction.
18. Give the electronic configuration of the :
a) d – orbitals of Ti in [Ti(H2O)6]3+ ion in the octahedral crystal field.
b) Why is this complex coloured ? Explain ( e- in d orbital)
19. a) Name a broad spectrum antibiotic and state two diseases for which it is prescribed.
b) Why is biothional added to the toilet soap.
20. Account for the following :
a) On addition of ozone gas to Kl solution. Violet vapours are obtained.
b) H3PO2 and H3PO3 act as good reducing agents white H3PO4 does not.
c) Chlorine water has both oxidising and bleaching properties.
21. What are antihistamines? How do they act on human body. Give two examples.
OR
Account for the following :
Aspirine drug helps in the prevention of heat attack.
Diabetic patients are advised to take artificial sweetness instead of natural sweetness.
Detergents are non biodegradable while soaps are biodegradable.
22. What is the significance of leaching in the
a) extraction of aluminium
b) Why are sulphide and carbonate ores converted into oxides.
23. a) Explain the cause and two consequences of lanthanoid contraction.
b) Give balanced chemical equation of two reactions in which KMnO4 acts as an oxidising agents in the acidic medium.
24. Predict the shape of the following molecules :
a) XeF6 b) ClF3 c)XeO3
25. a) Explain by hydrate isomerism in coordination compounds. Give an example.
b) NH3 is strong ligand. NH4+ ion is not why?
c) Draw all the optical isomers of [COcl(Cn)2(NH3)]2+.
26. Name the chief ores of Zinc and Mercury. Describe the reactions involved in the extraction of these metals from the respective ores.
27. Explain the following :
a) Thermit process is quite useful for repairing the broken parts of a machine.
b) Aquous solution of sodium chloride cannot be used for the isolation of sodium by electrolytic reduction method.
c) Carbon reduction process is not applied for reducing aluminium oxide to aluminium.
28. a) Write the name and draw the structure of each of the following complex compounds :
i) [Co (NH3)4(H2O)2]Cl2
ii) [Pt(NH3)4][NiCl4]
b) Explain as to how the two complexes of nickel [Ni(CN)4]2- and Ni(CO)4; have different structure but do not differ in their magnetic behaviour (Ni = 28)
OR
How is magnitude o affected by affected by
nature of ligand and
oxidation state of metal ion
Write the formula for the following co ordination compounds
Di chloridobis (ethane – 1,2 diamine) cobalt (iii)
Tetra ammine aquachloride cobalt (iii) cobalt
Potassium tetra hydroxyzincate (ii)
29. a) Describe the chemical reactions involved in manufacture of sulphuric acid by contact process.
b) Give the formula and describe the structure of noble gas species which is isostructural with
i) IBr2- ii) ICl4 iii) BrO3-
OR
Account for the following :
Sulphur in the vapour state is paramagnetic. Why?
Why SF6 is resistant to hydrolysis.
Bleaching of flowers by chlorine is permanent while that by sulphur dioxide is temporary explain.
PCl5- act as a chlorinating agent.
Bismith is a strong oxidising agent in the pentavalent state.
30. Give reasons :
a) The lower oxidation state of Mn is basic while the higher is acidic.
b) Mn (II) shows maximum paramagnetic character amongst divatent ions of first transition series.
c) In titration of FeSO4 with KMnO4 in acidic medium. Why is dil H2SO4 used instead of dil HCl.
d) Ce4+ is used as oxidising agent in volumetric analysis.
e) Zn2+ salts are white cu2+ salts are blue.
OR
CrO42- is strong oxidising agent while MnO42- is not.
Out of Ag2SO4, CuF2, MgCl2 and Cucl which would be coloured and why?
The radius of Fe2+ (z = 26) is less than that of Mn2+ (z = 25)
The lowest oxide of transition metal is basic, the highest is acidic.
The highest oxidation states is exhibited oxoanion of a soild.