Biology-1998

Q1. What induces parthenocarpy in grapes?
Ans1. Auxins.

Q2. What is the term used for the regions of a gene which become part of mRNA and code for the different regions of the proteins?
Ans2. Exons.

Q3. The venous blood in the lung has a PCO2 of 46 mm Hg. Should the alveolar PCO2 exceed or be less than 46 mm Hg to result in diffusion of CO2 from the blood into the alveolus?
Ans3. It should be less than 46 mm Hg.

Q4. Which part of the plant leaf is modified to form spines of Acacia and the sheath covering the leaf of Ficus elastica.
Ans4. Stipules.

Q5. Name the enzyme that can break and reseal one strand of DNA.
Ans5. Topoisomerase.

Q6. What does J-shaped growth curve of a population indicate?
Ans6. The J-shaped curve indicates that the factors of environmental
resistance do not produce zero growth to contain the exponential growth.

Q7. What forms the cambial ring in a dicot stem during the secondary growth?
Ans7. The cambial rings are formed by alternately forming secondary xylem.

Q8. Name the principal mineral anion in the extracellular fluid.
Ans8. Ca2+.

Biology -1999

Q1. Name the process in which bacteriophage picks-up a piece of DNA from one bacterial cell and transfers the same to another bacterial cell on infection.
Ans1. Transduction.

Q2. Which fraction of soil water is readily available to plants for absorption.
Ans2. Capillary water fraction .

Q3. What protects nitrogenase?
Ans3. ‘Leghemoglobin’ combines with oxygen and maintains anaerobic environment to protect nitrogenase.

Q4. Name two plants that produce rhizomes.
Ans4. Ginger, Turmeric.

Q5. Why is oxytocin called as ‘Birth Hormone’?
Ans5. Oxytocin helps in uterine contraction and the onset of labour at the time of child-birth.

Q6. From which germ layers do the following organs differentiate :
(i) Kidney
(ii) Urinary bladder

Ans6. Kidney and the urinary bladder differentiate from mesoderm.

Q7. What provided energy for abiotic synthesis on the primitive earth?
Ans7. ‘Lightning and solar radiation’ provided energy for abiotic synthesis on the primitive earth.

Q8. Name the two curable sexually transmitted diseases.
Ans8.
(i) Syphilis, and
(ii) gonorrhoea are curable sexually transmitted diseases.

Biology-2000

Q 1. What is meant by trisomic condition? (1 mark)
Ans1. Trisomy is the presence of an extra chromosome i.e., so that a particular chromosome is present in three copies.

Q 2. State the presence or absence of sinus venous in a fish and a mammal. (1 mark)
Ans2. Fish and mammals do not have sinus venosus because a sufficiently high blood pressure cannot be maintained in the open spaces.

Q 3. Which type of cartilage is present between vertebrae to allow limited movement? (1 mark)
Ans3. White fibrocartilage

Q 4. Name any two breeds of wild rock pigeon that have been developed through artificial selection. (1 mark)
Ans4. (i) Pouter, and
(ii) Jacobin.

Q 5. Which chromosomes are called autosomes? (1 mark)
Ans5. Autosome is any chromosome other than a sex chromosome. In humans they are 22 pairs.

Q 6. When is a tumour referred to as malignant? (1 mark)
Ans6. A tumour is called malignant, if it has the capacity to undergo metastasis.

Q 7. What are the two factors that contribute for the dissociation of oxyhaemoglobin in the arterial blood to release molecular oxygen in an active tissue? (1 mark)
Ans7. PO2 in the tissues lower than arterial blood, and PCO2 in the tissues higher than arterial blood.

Q 8. Which one of the following is fatal unless oral rehydration therapy is administered :
(i) Whooping cough (ii) Cholera (iii) Tetanus (1 mark)

Ans8. Cholera

Chemistry-1996-Set I

Q1) Write the state of hybridisation of Boron in BCI3. (Marks 1)
Ans1)In BCl3 , Boron is sp2 hybridized.

Q2) What are the coordination numbers of each of the ions present in the cubic close packed structure of CaF2 at ordinary temperature and pressure? (Marks 1)
Ans2) Coordination Number for Ca2+ is 8 and for F- is 4.

Q3) The rate constant of a reaction is 2 x 10-2 L mol-1 s-1. What is the order of the reaction?
(Marks 1)

Ans3) Order of the reaction is two.

Q4) Give the IUPAC name of the following compound:
O

CH3CHCCHOCH2CH3

CH3 CH3 (Marks 1)
Ans4) The name of the compound is
O

CH3CHCCHOCH2CH3

CH3 CH3
2-ethoxy-4-methylpentanone-3.

Q5) Which alkali metal carbonate decomposes on heating to liberate CO2? (Marks 1)
Ans5) Li2CO3

Q6) Name the first element of the 3-d transition metal series.
(Marks 1)

Ans6) Scandium.

Q7) Give the IUPAC name of the linkage isomer of [ (NH3)3 Pt-NO2 ]Cl. (Marks 1)
Ans7) The linkage isomer of [ (NH3)3 Pt-NO2 ]Cl will be [(NH3)3 Pt (ONO)]Cl. It’s IUPAC name is triamminenitritoplatinum(11) chloride.

Chemistry-1997-Set I

Q 1 State the physical significance of 2.
Ans. 1 2 is the measure of probability of finding an electron in the region around the nucleus.

Q.2 Write which one out of O+2 and O–2 is more stable?
Ans. 2 O+2 is more stable as compared to O-2 because bond order of O+2 is 2.5 while that of O-2 is 1.5.

Q 3 Write an expression in the form of a chemical equation for standard enthalpy of formation of for CO?
Ans. 3 C + 1/2 O2(g) —-> CO(g)

Q 4 Write an expression to relate molar conductivity of an electrotype to its degree of dissociation?
Ans.

Q 5 What is the ‘ambident group’ ? Give an example.
Ans. 5 Ambident group is one which has more than one attacking site for example -C[-]N- is an ambident nuclleophile.

Q 6 Indicate a chemical reaction involving a homogeneous catalyst ?
Ans. 6 SO2(g) + 1/2 O2(g) —————–> SO3(g)
……………………………………NO(g)

Q 7 Mention two main function of carbohydrates in plants ?
Ans. 7 Two main function of carbohydrates are :
(1) Cellulose is the chief structural material of plants.
(2) Carbohydrates act as energy storing devices of plants.

Chemistry-1997-Set II

Q 1 What values are permitted for the magnatic quantum number, m for for an electron with angular momentum number, l=2 ?
Ans. 1 When l=2 m=-2 , -1 , 0 , +1 , +2.

Q 3 Name the metal ion with tripositive charge represented by the configuration 1s(2) 2s(2) 2p(6) 3s(2) 3p(6) 3d(6).
Ans. 2 Chromium (Cr)

Q 4 How is the unit of molar conductivity arrived at ?
Ans. Molar conductivity (m) = K x 1000 / Cm (m) = ohm-1cm-1 / moles/cm3

Q 5 Which one among the following is strongest oxidising agent : ClO4-, BrO4-, IO4-.
Ans. BrO4-

Q 11 Calculate the kinetic energy of moving electron which have wavelength of 4.8 pm. (Mass of electron = 9.11 x 10-31 kg, h = 6.63 x 10-34Js)
Ans. 5 = 4.8 pm = 4.8 x 10-12 m
= h / mv
v = 6.6 x 10-34 Js / 9.1 x 10-31 Kg x 4.8 x 10-12m
= 6.6 x 109 / 9.1 x 4.8
= 0.151 x 109 m/s
= 1.151 x 108 m/s
K.E. = 1/2 mv2
= 1/2 x 9.1 x 10-31 x (1.51 x 108)2
= 1/2 x 20.74 x 1015
= 10.37 x 1015 J

Chemistry-1997-Set III

Q 2 Which one out of O+2 and O-2 is more stable.
Ans. 1 O+2 is more stable because its bond order is higher than O-2.

Q 5 How is the unit of molar conductivity arrived at?
Ans. 2 Molar conductivity (m) = K x 1000 / cm
(m) = ohm-1 cm-1 / moles/cm3

Q 6 Which one among the following is strongest oxidising agent : ClO4-, BrO4-, IO4-
Ans. 3 BrO4-

Q 12 The solubility of Ba(OH)2.8H2O in water at 288k is 5.6 g per 100 g of water. What is the molality of the hydroxide ions in the saturated solution of barium hydroxide at 288k? (Atomic mass : Ba=137, O=16, h=1)
Ans. 4 WB = 5.6 g , WB = 100 gm = WB. 100 / MB.WB
= 5.6 x 1000 / 315 x 100 = 0.17
Molarity of Ba(OH) 2.8 H2O = 0.17
Since, one mole Ba(OH) 2.8 H2O will finish two moles of OH- ions.
Molarity of OH- ion = 2 x 0.17 = 0.34 m

Q 16 Consider the following data for the reaction : A + B —–> Products.
Run Initial Conc Initial Conc Initial rate(mols-1)
A B
1 0.10M 1.0M 2.1×10-3
2 0.20M 1.0M 8.4×10-3
3 0.20M 2.0M 8.4×10-3

Determine the order of reaction with respect to A and with respect to B, and the over all order of the reaction.
Ans. Divide Expt. No. (i) and (ii) K [A] [B] = rate of reaction
K[0.20] [1.0] /K[0.10] [1.0] = 8.4 x 10-3/2.1 x 10-3
2 =4 or 2=22 or = 2
So order w.r.t A=2
From Expt.No.(ii) and (iii) it is clear that rate of reaction does not change
in concentration of B, So order W.r.t. B is 1, i.e Rate = k[A]2 [B]o
over all order of reaction = 2

Chemistry-1998-Set I

Q1) Write the MO electronic configuration of a diatomic molecule having a bond order of three? (Marks 1)
Ans.1) 1s2 *1s2 2s2 *2s2 2px2= 2py2 2pz2 (for example – N2)

Q2) What are non-stoichiometric compounds? (Marks 1)
Ans.2) Non-stoichiometric compounds are in which the ratio of the cation’s to the anions is different from that indicated by the chemical formula.

Q3) Complete the nuclear reaction expression? (Marks 1)
Ans.3) 27Co59 (d, p) 27Co60

Q4) Write the IUPAC name of : (Marks 1)

Ans4) 2 – Phenyl propanol.

Q5) Why do noble gases form compounds with fluorine and oxygen only? (Marks 1)
Ans5) Noble gases have very stable configuration and therefore only the most electronegative elements like fluorine and oxygen are able to oxidise them.

Q6) Why is hydrochloric acid not used to acidify a permanganate solution in volumetric estimations of Fe2+ or C2O42- ? (Marks 1)
Ans6) HCl is not used to acidify a permanganate solution is volumetric estimations of Fe2+ or C2O42- because HCl gets oxidised to Cl2 and some quantity of permanganate is used for this.

Chemistry-1998-Set II

Q3) Write the IUPAC name of [Ni(CN)4]2- ion. (Marks 1)
Ans3) IUPAC name of [Ni(CN)4]2- ion is tetracyanonickelate (II) ion.

Q4) Write the IUPAC name of : (Marks 1)
O

CH3CCHCH3

CH3

Ans4) IUPAC name of
O

CH3CCHCH3 is 3-Methyl-2-butanone.

CH3

Q6) Complete the nuclear reaction expression : (Marks 1)
13AI27(,n)….

Ans6) 13Al27 (,n)15P30

Q9) Why do azo dyes not impart fast colour to fabrics? (Marks 1)
Ans9) Azo dyes do not impart fast colour to fabrics because their interaction with the fabric is one of surface adsorption.

Chemistry-1999-Set I

Q 1 Define an atomic orbital. What does angular momentum quantum number tell about an orbital ?
Ans. 1 Orbital is three dimensional region in space around the nucleus where probability of finding electron is maximum. Angular memento determine the shape of the orbital.

Q 2 Which one of the two, O-2 or O-22 has higher bond order and why?
Ans. 2 O-2 has higher bond order.
O-2 = s 2s2 s*2s2 s2p2z 2p2x 2p2y 2p2x *2p1y
B.O. = 1/2 (8-5) = 1.5
B.O. of O -22 = 1/2 (8-6) = 1

Q 3 Define dislocation in crystal.
Ans. 3 Lattice imperfection extending along a line is known as line defect or dissociation.

Q 4 Write an example of neutral molecule which is isoelectronic to CIO-.
Ans. 4 CIF of HOCl or OF2

Q 5 Express the relationship between degree of dissociation of an electrolyte and its molar.
Ans. 5 = m / m

Q 6 What for are quaternary ammonium salts widely used?
Ans. 6 For detergent.

Q 7 What is meant by Faraday constant?
Ans. 7 It is the charge carried by one mole of electrons or quantity of charge required to deposit one gram equivalent of any element.

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