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86501.

(A) When conc. H_(2) SO_(4) comes into contact with cane sugar, the later becomes black. (R ) Conc.H_(2)SO_(4) dehydrate sugar to black residue carbon

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Both (A) and (R ) are true and (R ) is the CORRECT EXPLANATION of (A)
Both (A) and (R ) are true and (R ) is not the correct explanation of (A)
(A) is true but (R ) is FALSE
Both (A) and (R )are false

ANSWER :A
Discussion
86502.

A: When butyne-2 is reacted with Na/liq. NH_(3) then trans-butene-2 is formed. R : This reaction proceeds through free radical intermediate.

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If both Assertion & Reason are true and the reason is the CORRECT explanation of the assertion, then mark (1).
If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
if Assertion is true STATEMENT but Reason is false, then mark (3)
If both Assertion and Reason are false statements, then mark (4)

Answer :2
Discussion
86503.

(A): When a finely divided active carbon or clay is stirred into a dilute solution of a dye, the intensity of colour in the solution is decreased. (R): The dye is adsorbed on the solid surface of carbon or clay

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Both (A) and (R) are TRUE and (R) is the CORRECT EXPLANATION of (A) 
Both (A) and (R) are true and (R) is not the correct explanation of (A) 
(A) is true but (R) is false 
(A) is false but (R) is true 

ANSWER :A
Discussion
86504.

(a) when a chromite ore (A) is fused with an aqueous solution of sodium carbonate in free excess of air , a yellow solution of com[ound (B) is obtained . This solution is filtered and acidified with sulphuric acid to form compound (C ) . Compound (C ) on treatment with solution of KCl gives orenge crystals of compound (D ) . Write the chemical and actinoids : (i) Greater range of oxidation states of actiniod as compared to lanthonoids . (ii) Greater actinoid contraction as compared to lanthanoid contraction . Lower ionisation enthalphy of early actinoids as compared to the early lanthanoids.

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Solution : (a) chemical formula of comounds A to D are given as inder :
` A=FeCr_(2)O_(4)``B=Na_(2)CrO_(4)``C= Na_(2)Cr_(2)O_(7)``D=K_(2)Cr_(2)O_(7)`
(b) (i) Greater range of oxidation states actioniods than lanthanoids is because 5f, 6d and 7s levels in actinoids are of comparable enerrgies .
(ii)This is due to poorer shielding by 5f ELECTRONS in actinoids as compared to shielding by 4f electronss inlanthanoids .
(iii) In actinoids , 5f electrons are more effectiely shielded from the nuclear CHARGE than the 4g electrons of the correspomding lanthanoids , Since the outer electrons are LESS firmly HELD , they are available for bonding in the actinoids .
Discussion
86505.

(a) When 19.5 g of F-CH_(2)-COOH (Molar mass = 78" g mol"^(-1)) is dissolved in 500 g of water, the depression in freezing point is observed to be 1^(@)C. Calculate the degree of dissociation of F-CH_(2)-COOH. [Given : K_(f) for water = 1.86 K kg mol^(-1)] (b) Give reasons : (i) 0.1 M KCl has higher boiling point than 0.1 M Glucose. (ii) Meat is preserved for a longer time by salting.

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Solution :(a) Number of moles of `F-CH_(2)-COOH=(19.5)/(78)=0.25` moles
Molality of the solution `=(0.25)/(500)xx1000=0.5" mol kg"^(-1)`
Using the following equation
`Delta T_(f)=iK_(f)m`, where I is van.t Hoff factor
Substituting the values in the above equation, we have
`1K=ixx1.86" K kg mol"^(-1)xx0.5" mol kg"^(-1)`
or `""i=(1)/(1.86xx0.5)=(1)/(0.93)=1.075""...(i)`
`I-"CII"_(2)-COOH to F-UNDERSET(x)(CH_(2)COO^(-))+underset(x)(H^(+))`
where x is degree of dissociation.
TOTAL number of moles `=1-x+x+x=1+x`
`i=(1+x)/(1)""...(ii)`
From (i) and (ii), we have
`1+x=1.075` or x = 0.075
Degree of dissociation = 0.075 or 7.5%
(b) (i) KCl dissociates to give `K^(+)` and `Cl^(-)`. As the concentration of particles in 0.1 M KCl is more than that of 0.1 M glucose, boiling point of KCl is higher.
(ii) Whater is taken out of bacteria into the solution of SODIUM chloride as a result of osmosis. Therefore bacteria do not SURVIVE.
Discussion
86506.

(a) When a bright silver object is placed in the solution of gold chloride, it acquires a golden tings but nothing happens when it is placed in solution of copper chloride. Explain this behaviour of silver. [Given :E_(Cu^(2+//)Cu)^(@)=+0.34 V, E_(Ag^(+//)Ag)^(@) =+0.80 V, E_(Au^(3+//)Au)^(@) =+1.40V](b) Consider the figure given above and answer the following questions : (i) What is the direction of flow of electrons? (ii) Which is anode and which is cathode?(iii) What will happen if the salt bridge is removed ? (iv) How will concentration of Zn^(2+) and Ag^(+) ions be affected when the cell functions ? (v) How willconcentration of these ions be affected when the cell becomes dead ?

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Solution :(a) When a bright silver object is placed in gold chloride

`E_("Cell")^(@) = E_("cathode")^(@) - E_("anode")^(@)`
`E_("cell")^(@) = E_(Au3+//Au)^(@)-E_(Ag+//Ag)^(@)`
= 1.40 - 0.80 = 0.60V
`E_("cell")^(@) = + 0.60V`
When silver is palced in copper chloride solution

`E_("cell")^(@) = E_(C)^(@) - E_(A)^(@)`
`=E_(Cu2+//Cu)^(@)-E_(Ag+//Ag)^(@) = 0.34 - 0.80`
`E_("cell")^(@) = - 0.46V`
As `E^(@)` cell is positive for gold chloride solution. Hence reaction is feasible and silver object acquires a GOLDEN tings but `E^(@)` cell is negative for copper chlrodie. Hence, nothing happens with it.
(b) (i) Electrons flow from negative pole to positive pole (from left to right) i.e., from anode to cathode.
(ii) The Zinc electrode at which oxidation takes place is anode and silver electrode WHERER reduction takes places is cathode.
(iii) Circuit will not be completed, flow of electrons will stop and hence the current stops flowing.
(iv) Concentration of `Zn^(2+)` decreases and `Ag^(+)` ions increases when the cell functions.
(v) When E cell = 0, EQUILIBRIUM is reached and concentration of `Zn^(2+)` and `Ag^(+)` ions will not CHANGE.
Discussion
86507.

(a) When 1.5 g of a non-volatile solute was dissolved in 90 g of benzene, the boiling point of benzene is raised from 353.23 K to 353.93 K. Calculate the molar mass of the solute. (b) When fruits and vegetables that have dried up are placed in water, they swell and return tooriginal form. Why? Would temperature increase accelerate the process ?

Answer»

Solution :(a) ` Delta T_b = 353.93 - 353.23 = 0.7K`
Molality of the solution ` = m = (1.5//M_B)/(90) xx 1000 = (1.5//1000)/(M_B xx 90) = (150)/(9M_B)`
Applying the relation : `Delta T_b = K_b xx m`
Substituting the VALUES in the above equation, we have
`0.7 = 2.52 xx (150)/(9 M_B)`
`M_B = (2.52 xx 150)/(0.7 xx 9) = 60` g/mol
(b)Fruits and vegetables SWELL in water due to osmosis. An increase in temperature ACCELERATES the process of osmosis.
Discussion
86508.

(a) What type of semiconductor is obtained when silicon is doped with boron ? (b) What type of magnetism is shown in the following alignment of magnetic moments ? {:(uarr,uarr,uarr,uarr,uarr):} (c) What type of point defect is produced when AgCl is doped with CdCl_(2) ?

Answer»

Solution :(a) A p-type semiconductor is obtained when silicon is doped with boron.
(b) Ferromagnetism is SHOWN in the given alignment of magnetic MOMENTS.
(C) Impurity defect is PRODUCED when AgCl is doped with `CdCl_(2)`.
Discussion
86509.

(a) What type of isomerism is shown by the complex [Co(NH_(3))_(5)(SCN)]^(2+) ? (b) Why is [NiCl_(4)]^(2-) paramagnetic while [Ni(CN)_(4)]^(2-) is diamagnetic ? (Atomic no. of Ni = 28) (c ) Why are low spin tetrahedral complexes rarely observed ?

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SOLUTION :(a) Linkage isomerism, (c ) They involve `SP^(3)` HYBRIDISATION. The 3d orbitals do not participate in hybridisation.
Discussion
86510.

(a) What type of deviation is shown by a mixture of ethanol and acetone 7 Give reason. (b) A solution of glucose (molar mass = 180 g mol^(-1)) in water is labelled as 10% (by mass). What would be the molallty and molarity of the 90lution ? (Density of solution = 1.2 g mL^(-1).)

Answer»

SOLUTION :(a) It shows positive deviation. It is due to weaker interaction between acetone and ETHANOL than ethanol-ethanol interactions.
(B) Given : `W_(B) = 10 g , W_(s) = 100 g , W_(A) = 90 ` g
`M_(B) = 180 g//mol & d = 1.2 `g/mL
M = `(Wt % xx "DENSITY" xx 10)/("Mol.wt.")`
M = `(10 xx 1.2 xx 10)/(180)`
= 0.66 M or 0.66 mol/L
= 0.66 M
m = `(W_(B) xx 1000)/(M_(B) xx W_(A) "(in g)") `
`m = (10 xx 1000)/(180 xx 90)`
= 0.61 m or 0.61 mol/kg
Discussion
86511.

a) What type of isomerism is exhibited by the square planar complex of type M_(ABXY)? How many of these isomers are possible?

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Solution :Square planar complex of the type `M_(ABXY)` [where A, B, X, L] are unidentate ligands)
SHOWS three ISOMERS among them two CIS and one trans isomers.
Discussion
86512.

(a) What type of a battery is the lead storage battery? Write the anode and the cathode reactions and the overall reaction occuring in a lead storage battery when current is drawn from it. (b) In the button cell, widely used in watches, the following reactions takes place: Zn(s)+Ag_2O(s)+H_2O(l) to Zn^(2+) (aq)+2OH^(-) (aq) Determine E^@ and Delta G^@ for the reaction:

Answer»

Solution :(a) It is secondary cell
ANODE reaction:
`Pb+SO_4^(2-) to PbSO_4(s)+2e^(-)`
`Cathode reaction: PbO_2+4H^+ +SO_(4)^(-) +2e to PbSO_+2H_2O`
`Net reaction: Pb+PbO_2+2H_2SO_4 to 2PbSO_4+2H_2O`
(b) `E_(cell)^@=E_(cathode)^@-E_(anode)^@ `
=0.80V-(-0.76)V
=+1.56 V
`Delta RG^@=-nFE_(cell)^@`
`=-2 times 96500 C mol^-1 times 1.56 V`
`=-301080 J mol^-1` or `-301.08KJ mol^-1`
Discussion
86513.

A what temperature, the rate of effusion of N_(2) would be 1.625 times that of SO_(2) at 50^(@)C ?

Answer»

135K
373K
546 K
303K

Solution :`( r ( N_(2)))/( r(SO_(2))) = 1.625 =SQRT(((3RT( N_(2)))/(28))/((3Rxx 323)/(64)))`
`= 1.625 = sqrt(( 16 xx T ( N_(2)))/( 7 xx 323))`
`:. T ( N_(2)) = 373 K`
Discussion
86514.

(a) What is van't Hoff factor? What types of values it can have ifthe solute molecules undergo (i) Dissociation ? (ii) Association? (b) How many mL of a 0.1 M HCl solution are required to react completely with 1 g of a mixture of Na_(2)CO_(3) and NaHCO_(3) containing equimolar amounts of both ? (Molar mass : Na_(2)CO_(3)=106g,NaHCO_(3)=84 g)

Answer»

Solution :The van't Hoff factor I (named after J.H. van't Hoff) is a measure of the effect of a solution upon colligative properties such as osmotic pressure, relative lowering in vapour pressure elevation of boiling point and FREEZING point depression. The van't Hoff factor is the ratio between the actual concentration of particles produced when the subtance is dissolved , and the concentration of a substance as CALCULATED from its mass.
Dissociated solutes: The degree of dissociation is the fraction of the original solute molecules that have dissociated . It is usually indicated by the Greek SYMBOL `alpha`. There is a SIMPLE relationship between this parameter and the van't Hoff factor. If a fraction `alpha` . There is a simple relationship between this parameter and the van't Hoff factor. If a fraction `alpha` of the solute dissociates into n ions, then
`""i=alpham+(1-alpha)=1+alpha(n-1)`
For example, the dissociation:
`""KCl hArr K^(+)+Cl^(-)`
yields n=2 particles, so that `i=1+alpha`
Associated solutes : Similarly, if a fractiion `alpha` of n moles of solute associate to form one mole of an n-mer (dimer , trimer, etc.) , then
`""i=1-(1-(1)/(n))alpha`
For the dimerisation of acetic acid in benzene : `2CH_(3)COOH hArr (CH_(3)COOH)_(2)`
2 moles of acetic acid assoicate to form 1 mole of dimer, so that
`""i=1-(1-(1)/(n))alpha=1-(alpha)/(2)`
(b) Let the amount of `Na_(2)CO_(3)` be X
Let teh amount of `Na_(2)HCO_(3)` be 1-X
Since no. of moles of both are equal
`(X)/(N(Na_(2)CO_(3)))=(1-X)/(M(NaHCO_(3)))`
`(X)/(106)=(1-X)/(84)`
84X=106-106X
X=0.5578
`nNa_(2)CO_(3)=0.5578//106=0.00526`
`nNaHCO_(3)=0.00526`
`Na_(2)CO_(3) + 2HCl to 2NaCl + CO_(2) + H_(2)`
`NaHCO_(3) + HCl to NaCl + CO_(2) + H_(2)O`
`M_(1)V_(1) = 2M_(2)V_(2)+ M_(3)V_(3)`
`0.1 xx V_(1)=2xx0.00526 + 0.00526`
`V_(1)=(0.01578)/(0.1)=0.1578 L`
`V=157.8 ml.`
Discussion
86515.

(a) What kind of directive effect would you expect the acetamido group (CH_(3)CONH-) to have?

Answer»

SOLUTION :(a) Ortho/para DIRECTOR
Discussion
86516.

(a) What is the significance of the following in crystal structure : (i) a, b and c (b) (ii) alpha, beta and gamma (b) What are the values of the above in tetragonal structure ? Give an example of a solid having this structure.

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Solution :(a) (i) a, b and c represent the DIMENSIONS along the THREE edges of the unit CELL.
(ii) `alpha, beta and gamma` represent the angles between the edges, `alpha` between b and c, `beta` between a and c and `gamma` between a and b.
(b) In tetragonal structure, the values are as under :
`a=b ne c`
`alpha=beta=gamma=90^(@)`
Tin oxide, `SnO_(2)`, is an example of this TYPE of structure.
Discussion
86517.

(a) What is the role of cryolite in the metallurgy of aluminium ? (b) How is leaching carried out in case of low grade copper ores? (c) Why is zinc not extracted from zinc oxide through reduction using CO?

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Solution :(a) Cryolite is added to bauxite ore before electrolysis because of the following reasons :
(i) It ACTS as a solvent.
(ii) It lowers the melting point of alumina to about 1173 K.
(iii) Addition of cryolite to alumina INCREASES the electrical conductivity.
(b) Copper is leached out from low grade copper by using acid in the presence of air when copper GOES into the solution as `Cu^(2+)`IONS.
`Cu(s) + 2H^(+)(aq) + 1/2O_2(g) to Cu^(2+) (aq) + H_2O(l)`
The solution containing` Cu^(2+)` ions is TREATED with scrap iron or `H_2`.
`Cu^(2+) (aq) H_2(g) to Cu(s) + 2H^(+) (aq)`
(c) In Ellingham diagram, the `DeltaG_r` vs T plot represcntingCO, `CO_2` lies above `DeltaG^@` vs T plot of Zn, ZnO. Therefore, CO cannot act as reducing agent for the reduction of ZnO.
Discussion
86518.

a) What is the organic compound formed in the following :

Answer»

SOLUTION :
Discussion
86519.

(A): Water is the most stable hydride of chalcogens (R): Among M-H bonds of chacogen hydrides, O-H bond is more stable.

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Both (A) and (R ) are TRUE and (R ) is the correct EXPLANATION of (A)
Both (A) and (R ) are true and (R ) is not the correct explanation of (A)
(A) is true but (R ) is FALSE
Both (A) and (R )are false

Answer :A
Discussion
86520.

(a) What is the limiting value of K as T increases ? (b) Which reaction will have the greater temperature dependence for the rate constant one with small value of E_(a) or one with large value of E_(a)

Answer»

Solution :`(a) 10^(14.34) SEC^(-1)`
`(b)(dk)/(DT)=(E_(a))/(RT^(2))`
Thus `(dK)/(dT) prop E`, and higher value of `E_(a)` will have greater effect.
Discussion
86521.

(A)What is the final product in each reaction? (i) C_(2)H_(5)OH overset(I_(2))underset(NaOH)(to) (ii) CHCI_(3) overset(Ag)underset("Heat")(to)? (iii) CHCI_(3) overset(HNO_(3))(to)? (iv) CCI_(4) overset(Fe//H_(2)O)(to)? (v) C_(6)H_(5)NH_(2) overset(CHCI_(3))underset(KOH)(to)? (vi) C_(4)H_(9)Br overset(NaNO_(2)//C_(2)H_(5)OH)(to)? (ix) CH_(3)Li overset(CH_(2)=CH_(2))(to)? (x) (CH_(3))_(3) C CI overset((CH_(3))_(2)Zn)(to)? (x i) H_(2)C=overset(CH_(3))overset(|)C-CH_(2)CH_(3)overset(IBr)(to)? (x i i) CH_(3)-CH-CH_(2) overset(NBS)(to)? (x iii) CH_(3)-underset(CH_(3))underset(|)CH-CH_(2)CIoverset(NaI)underset("Acetone",Delta)(to)? (x iv) R_(3)Mg X overset((CH_(3))_(2)CO //H_(2)O)(to)? (xv) CH_(3)-underset(Br)underset(|)CH-underset(CH_(3))underset(|)CH-CH_(3)+HBr to ? (xvi) CH_(3)-underset(CH_(3))underset(|)CH-underset(OH)underset(|)CH-CH_(3)+HBr to? (x x) CH_(3)-overset(CH_(3))overset(|)underset(CH_(3))underset(|)C-underset(CI)underset(|)CH-CH_(3)+KOH(alc) to? (x x i)(CH_(3))_(3)C-CH_(2)Br+KOH (alc) to ? (x x ii) CH_(3)-overset(CH_(3))overset(|)underset(CH_(3))underset(|)C-CH_(2)Br+C_(2)H_(5)OH overset("Heat")(to)? (B) (i) C_(6)H_(5)CH_(2)CH_(3) overset(Br^(2))underset(hv)(to)? (ii) C_(6)H_(5)CH_(2)CH_(3) overset((i) Br_(2),"heat ,light")underset((ii) NaCN,H_(2)O //H)(to)? (iii) CICH_(2)CH_(2)CH_(2)COPh overset(KOH)underset(MeOH)(to)?

Answer»

SOLUTION :
Discussion
86522.

(a) What is the difference between a colloidal solution and an emulsion? Give one example of each. (b) What are emulsifiers?

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SOLUTION : (a) In a colloidal solution, the dispersed phase is a solid and the dispersion medium is liquid. In an emulsion, both the dispersed phase and the dispersion medium are liquid. Example: Colloidal sol - cell fluids, muddy water.
Emulsion - milk, cold cream
(b) EMULSIFIERS: The substance which are added to stabilise the emulsions are called emulsifiers. Example: Soaps of various KINDS and lyophilic colloids (PROTEINS, gum etc.)
Discussion
86523.

(a) What is meant by the term 'Broad spectrum antibiotics' ? Explain. (b) What are artificial sweetening agents ? Give two examples. ("c") What problem arises in using alitame as artificial sweetener ?

Answer»

Solution :(a) These are the antibiotics which are effective several types of harmful micro-organisms. Therefore, these are used to cure a VARIETY of diseases. For example, chloromphenicol, is effective against a variety of diseases such as TYPHOID, acute fever, dusentary, WHOOPING cough, eye infections, certain urine infections, etc. Other broad spectrum antibiotics are tetracycline , olfaxacin etc.
(b) The CHEMICAL substances which give sweetening effect to food but do not add any calorie to our body are called artificial sweetening agents. For example, saccharin, aspartame.
(c) Alitame is a high potency artificial sweetening agent. Therefore , it POSES a problem to control the sweetness of the food.
Discussion
86524.

(a) What is meant by term 'coordination number' ? (b) What is the coordination number of atoms : (i) in a cubic close packed structure (ii) in a body centred cubic structure.

Answer»

Solution :(a) Coordination number gives the number of nearest neighbours with which a given atom is in contact. In CASE of IONIC crystals, coordination number in the crystal is the number of oppositely charged IONS surrounding that ion.
(B) (i) 12 (ii) 8.
Discussion
86525.

(a) What is meant by polymerisation? Name the monomer used in the preparation of Polyvinyl Chloride (PVC).(b) Write partial structure of the following polymers.(i) Poly propene (ii) Teflon(iii) Neoprene

Answer»

SOLUTION :The process of formation of polymers from the RESPECTIVE monomers is called polymerisation. (b) (i) Poly propene.
`[-CH_(2)-overset(CH_(3))overset(|)(C)H]_(N)`
(ii) TEFLON `[CF_(2)-CF_(2)-]_(n)`
(iii) Neoprene `[-CH_(2)-overset(CL)overset(|)(C)=CH-CH_(2)-]`.
Discussion
86526.

(a) What is meant by Hydroboration-oxidation reaction ? Illustrate it with an example. (b) Predict the major product of acid catalysed dehydration of 1-methylcyclohexanol.

Answer»

Solution :HYDROBORATION- oxidationreaction
thisreactioninvolvesthe additionof diboraneto analkenefollowed by oxidationwith alkaline`H_2O_2`
`6CH_3 -CH =CH_2 +B_6 H_6 OVERSET(THF) to 2 (CH_3 CH_2 CH_2) _3 B(CH_3 CH_2 CH_2) _3 B +3H_2 O_2 overset(OH^(-) ,H_2 O) tounderset("Propan -1-ol ") (3CH_2 CH_2 CH_2 -OH +H_3 BO _3`
Thealcoholobtainedis dueto anti-Markownikov.sadditionof waterto alkene .
Discussion
86527.

(a) What is meant by disproportionation of an oxidation state ? Give one example.

Answer»

SOLUTION : (a) When any atom or ion UNDERGO oxidation and reduction simultaneously it is called disproportionation.
`2Cu^(+) toCu^(+2) + Cu`
Discussion
86528.

(a) What is iodoform test? (b) Discuss the main chemical properties of C CI_(4)

Answer»

Solution :(a) Compounds containing `CH_(3) CH(OH)` or `CH_(3)-overset(O)overset(||)C-` structural units, when heated with iodine and an aquoeus solution of sodium carbonate or sodium HYDROXIDE, give yellow precipitate of iodoform. Therefore this reaction is of diagnostic value and is used in qualitative analysis to detect these structural units under the name iodoform test.
i.e `2NaOH+I_(2) to UNDERSET("Sod. hypoiadite")(NaOI+NaI+ H_(2)O)`
`R- overset(OH)overset(|)CH-CH_(3)+NaOI overset("Oxidation")to R-overset(O)overset(||)C-CH_(3)+NaI+H_(2)O`
`R-overset(O)overset(||)C-CH_(3)+3NaOI overset("lodination")to R-overset(O)overset(||)C-Cl_(3)+3NaOH`
`R-overset(O)overset(||)C-Cl_(3)+NAOH overset("Hydrolysis")to CHI_(3)+R-overset(O)overset(||)C-ONa`
(b) Some chemical properties of `C CI_(4)` are :
(i) Reduction :`C Cl_(4)+ 2[H] overset(Fe//H_(2)O)CHCl_(3)+HCl`
(ii) Hydrolysis : `C Cl_(4)+4KOH to underset("Unstable")([C(OH)_(4)]) to CO_(2)+ 2H_(2)O`
`CO_(2)+2KOH to K_(2)CO_(3)+ H_(2)O`
Discussion
86529.

(a) What is Hinsberg's reagent? How is it used to distinguish a primary amine from a secondary amine?

Answer»

Solution :Hinsberg.s reagent is Benzenesulfonyl chloride.
(a) PRIMARY amine REACTS with benzenesulfonyl chloride to form N- ETHYL benzenesulfonamide.
Discussion
86530.

(a) What is enzyme catalysis ? Give an example. (b) What type of emulsion is milk ? Explain. (c ) Explain electrophoresis with a labelled diagram.

Answer»

SOLUTION :(a) For ANSWER,CONSULT section 12.
(b) Milk is oil in water (O/W) type emulsion.
(C ) For answer, consult section 22.
Discussion
86531.

(a) What is electrophoresis ? (b) Write two difference between sols and emulsions.

Answer»
Discussion
86532.

(a) What is Electrophoresis ? (b) What are catalytic promoters ? Given one example.

Answer»

Solution :(a) For ANSWER, consult SECTION 22
(b) For answer, consult section 10.
Discussion
86533.

(a) What is coordination isomerism? Give an example.

Answer»

SOLUTION :(a) COMPLEXES having the same molecular formula but the ligands are interchanged between the CATIONIC and anionic entities of DIFFERENT metal ions are CALLED co-ordination isomers and the phenomenon is called co-ordination isomerism.
E.g., `[Cr(NH_(3))_(6)] [CO(CN)_(6)]` and `[Cr(CN)_(6)][CO(NH_(3))_(6)]`
(b) Diammine silver (1) Dicyano argentate (i)
Discussion
86534.

(a) What is coagulation of sol ? name two methods by which a lyophobic sol can be coagulated. (b) What is the change in enthalpy and entropy during adsorption of gas on a solid ?

Answer»

Solution :(a) The process of settling of colloidal particles is called coagulation of the sol.
By electrophoresis or by BOILING or by adding an ELECTROLYTE or by mixing two oppositely charged SOLS.
(b) Enthalpy DECREASES or `DELTAH` is negative. Entropy decreases or `DeltaS` is negative.
Discussion
86535.

(a) What is Cannizaro's reaction ? Write its mechanism. (b) Discuss the structure of carbonyl group.

Answer»

Solution : (a) Cannizaro.s reaction : This reaction is shown by aldehydes having no `alpha`-H-atom. When such an aldehyde is treated with 50% of NaOH or KOH, it undergoes disproportionation to give an ACID and an alcohol. This reaction is called Cannizaro.s reaction.
`underset("BENZALDEHYDE")(2C_(6)H_(5)CHO)underset((50%))(NaOH)_((aq)) to underset("BENZYL alcohol")(C_(6)H_(5)CH_(2)OH)+underset("Sodium benzoate")(C_(6)H_(5)COONa)`
Mechanism : It involves the following mechanism

Discussion
86536.

What is an ambidentate ligand ? Name the type of structural isomerism arises when such ligand present in the complex.

Answer»

Solution :(a) Ligand which can ligate through TWO different atoms. Linakge isomerism.
(b) `K_(2)[Zn(OH)_(4)]` Potassium tetrahydroxidozincate (II).
Discussion
86537.

What is Brownain movement ? What is the cause for it ?

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Solution :The ZIG - zag MOVEMENT of COLLOIDAL particles in a colloidal solution is called Brownian movement. The Brownian movement is DUE to the continuous bombardment of the moving MOLECULES of the medium on colloidal particles.
Discussion
86538.

(a) What is ATP ? Why is it energy rich molecule ? (b) What causes deficiency of Vitamin K ?

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Solution :(a) ATP is ADENOSINE triphosphate . It is an energy rich molecules due to the HIGH repulsive FORCES between four negatively CHARGED oxygen ATOMS which are very close to each other.
(b) Leafy vegatables.
Discussion
86539.

(a) What is a triplet in DNA molecule ? (b) What does DNA and RNA stand for?

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Solution :(a) A triplet is a SEQUENCE of THREE BASES in a DNA molecules which directs the DNA MOLECULE to PRODUCE the same triplet in protein synthesis.
(b) DNA stands for Deoxyribose Nucleic Acids. RNA stands for Ribose Nucleic Acids.
Discussion
86540.

(a) What is (a) multimolecular colloid (b) macromolecular colloid and (c) associated colloid ? (b) Write the equation for the two steps involved in enzyme catalysis.

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Solution :(a) If large number of atoms and small molecules aggregate to form particles of colloidal size, then the colloid is multimolecular colloid. Macromolecules (POLYMER) which have colloidal dimension in a suitable medium disperse to form MACROMOLECULAR colloid. Some substances (molecules) of intermediate size at higher concentration aggregate to form colloidal particles. This is ASSOCIATED colloid.
(b) Step - 1 `underset("Enzyme substrate")(E+ S) to underset("activated complex")(ES^+)`
Step 2 : `ES^(+) to E + underset("Product")(P)`
Discussion
86541.

(a) What is a ligand ? Give an example of a bidentate ligand. (b) Explain as to how the two complexes of nickel, [Ni(CN)_(4)]^(2-)andNi(CO)_(4) have different structures but do not differ in their magnetic behaviour. (Ni = 28)

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Solution :(a) Ligands - The ions or molecules BOUND to the central atom / ion in the coordination ENTITY are CALLED ligands.
Example of a bidenate ligand : `H_(2)N CH_(2)CH_(2)NH_(2)`(ethylenediamine)
(b) `[Ni(CN)_(4)]^(2-)` is a square planar complex which is diamagnetic as no unpaired electron is present.
`[Ni(CO)_(4)]` is a tetrahedral complex which is diamagnetic due to absence of unpaired ELECTRONS.
Discussion
86542.

What is a homopolymer? Give an example.

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Solution :It is an addition polymerisation in which the polymer contains large number of same monomer units.
EX : - POLYETHYLENE, Teflon
`underset("Tetra fluoro ETHYLENE"("n"CF_(2)=CF_(2))overset("High pressure")underset("Peroxide catalyst")rarr [--overset(F)overset(|)underset(F)underset(|)C-overset(F)overset(|)underset(F)underset(|)C--]_(n)`
Discussion
86543.

(a) What happens when propanone is heated with H_(2) in the presence of Raney nickel? (b) Give the structures of A. B and C in C in the following : CH_(3)CHO overset(K_(2)Cr_(2)O_(7))underset(H_(2)SO_(7))rarrAoverset(PCl_(5))rarrBoverset(C_(6)H_(6))underset("Anhyd".AlCl_(3))rarr C.

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Solution :(a) Propan-2-ol is formed
(b) `underset((A))(CH_(3)COOH), underset((B))(C_(3)COCL), underset((C))(C_(6)H_(5)COCH_(3))`
Discussion
86544.

(a) What happens when : (i) sulphur dioxide is passed through an aqueous solution of Fe (III) salt ? (ii) Sulphur dioxide is passed through and aqueous solution of sodium carbonate ? (b) On passing H_(2)S through an aqueous solution of SO_(2), as a yellow turbidity is formed. Why ?

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Solution :(a) (i) `SO_(2)` being a reducing agent, reduces Fe (III) to Fe (II) salts.
`2overset(3+)(Fe)(aq)+SO_(2)(g) + 2H_(2)O (l) rarr 2 overset(2+)(Fe)(aq) + SO_(4)^(2-) (aq) + 4 overset(+)(H)(aq)`
(ii) Being acidic, `SO_(2)` decomposes `Na_(2)CO_(3)` FORMING sodium SULPHITE with evolution of `CO_(2)` gas.
`Na_(2)CO_(3)(aq) + SO_(2)(g) rarr Na_(2)SO_(3) (aq) + CO_(2)(g)`
(B) `H_(2)S` reduces `SO_(2)` to sulphur which appears as yellow TURBIDITY.
`2H_(2)S + SO_(2) rarr underset(("Yellow turbidity"))(3S) + 2H_(2)O`
Discussion
86545.

(a) What happens when acidified KMnO_(4) is treated with : (i) KI (i) H_(2)S (ii) KNO_(2) (b) What happens when KMnO_(4) is heated ? Give reaction.

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Solution :(a) `2KMnO_(4)+ 3H_(2)SO_(4)+ 10KI to K_(2)SO_(4)+ 2MnSO_(4)+ 8H_(2)O+ 5I_(2)`
(ii)`2KMnO_(4)+ 3H_(2)SO_(4)+ 5H_(2)S to K_(2)SO_(4)+ 2MnSO_(4)+ 3H_(2)O+ 5S`
(iii) `2KMnO_(4)+ 3H_(2)SO_(4)+ 5KNO_(2) to K_(2)SO_(4)+ 2MnSO_(4)+ 3H_(2)O+ 5KNO_(3)`
(B) `UNDERSET("Pot. permanganate")(2KMnO_(4)) overset(513K)to underset(" Pot. manganate")(K_(2)MnO_(4))+ MnO_(2)+ O_(2)`
Discussion
86546.

(a) What happens when acidified K_(2)Cr_(2)O_(7) is treated with : (i) H_(2)S (ii) KI (iii) FeSO_(4) (b) Write formula of : (1) Pyrolusite ore (ii) Chromite ore.

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Solution :(a) (i) `K_(2)Cr_(2)O_(7)+ 4H_(2)SO_(4)+ 3H_(2)S to K_(2)SO_(4)+ Cr_(2)(SO_(4))_(3)+7H_(2)O+ 3S`
(ii) `K_(2)Cr_(2)O_(7)+ 7H_(2)SO_(4)+ 6KI to 4K_(2)SO_(4)+Cr_(2)(SO_(4))_(3)+ 3I_(2)+7H_(2)O`
(iii) `K_(2)Cr_(2)O_(7)+ 7H_(2)SO_(4)+ 6FeSO_(4) toK_(2)SO_(4)+ Cr_(2)(SO_(4))_(3)+ Fe_(2)(SO_(4))_(3)+2H_(2)O`
(b) (i) `MnO_(2)` (ii) `FeO. Cr_(2)O_(3)`. or `FeCr_(2)O_(4)`
Discussion
86547.

a) What do we call a drug that binds to the receptor site and inhibit its natural function

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Solution :Antagonists are the drug that BINDS to the receptor SITE and INHIBIT its natural FUNCTION
Discussion
86548.

(a) What change occurs when AgCl is doped with CdCl_(2) ? (b) What type of semiconductor is produced when silicon is doped with boron ?

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SOLUTION :(a) Cationic vacancy is GENERATED.
(B) p-type SEMICONDUCTOR.
Discussion
86549.

(a) Whatchanges occuris the natureof egg proteins on boiling? (b)Name the types of bondingwhichstabilises the alpha - helixstructurein proteins .

Answer»

Solution :(a) On BOILING, proteinof egg getsdenatured. Thus,dueto coagulationwaterget absorbed.
(B) Hydrogen bondingbetween .
`- UNDERSET(O)underset(||)(C) - ` and `-NH_(2)` groupsofpeptide BOND .
Discussion
86550.

(a) What are ureides? (b) What are barbiturates? ( c) How urea is estimated?

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Solution :(a) Acyl derivatives of UREA are called ureides. They are of two types:
(i) SIMPLE ureides : These are obtained by the reaction of acid halides and urea. Acetyl urea is the example of this class.
(ii) Cyclic ureides : These are obtained by the reaction of dicarboxylic acid or their derivatives and urea. Barbituric acid is the example of this class.
(b) Barbiturates are the derivatives of barbituric acid in which two hydrogen atom of `CH_(2)` group have been replaced by alkyl or aryl groups. Examples are :

These are used as sedatives.
(c ) Urea is estimated by hypobromite method. A known volume of urea solution is treated with sodium hypobromite solution containing NaOH. The EVOLVED carbon dioxide is absorbed by NaOH and the volume of NITROGEN evolved measured in the nitrometer. From the volume of nitrogen, the AMOUNT of urea in the sample can be determined.
Discussion