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11201.

To prevent food from spoilage by micro organism, which substance is used ?

Answer»

Aspartame
Arneto
Salt of sorbic acid
Tetrazine 

ANSWER :C
Discussion
11202.

What modification can you suggest in the Hardy Schulze law ?

Answer»

SOLUTION :According to hardy Schulze law, the COAGULATING ion has charge opposite to that on the COLLOIDAL particles. Hence, the charge on colloidal particles is neutralized and coagulation occurs. The law can be MODIFIED to include the following :
When oppositely charged sols are mixed in proper proportions to NEUTRALIZE the charges of each otehr, coagulation of both the sols occurs.
Discussion
11203.

Which of the following statements are correct for SO_(2)gas ?

Answer»

It acts as bleaching AGENT in moist conditions.
It's molecule has linear geometry.
It's DILUTE solution is USED as disinfectant.
It can be prepared by the REACTION of dilute `H_2SO_4` with metal sulphide.

Answer :A::C::D
Discussion
11204.

Which of the following statement is wrong?

Answer»

`Mn^(3)` and `CO^(3)` are oxidizing agents is AQUEOUS solution
In highest oxidation STATES.the transition metals show acidic
All elements of 3d series exhibit variable oxidation states.
Metals in highest oxidation states are more stable in OXIDE then in fluorides

Solution :SC exhibit only +3 oxdn state
Discussion
11205.

Which one of the following material conducts electicity ?

Answer»

Diamond
Crystalline NaCl
Barium sulphate
Fused KCl

Answer :D
Discussion
11206.

The two strands in DNA are not identical but are complementary. Explain .

Answer»

Solution :The two strands in DNA moleucle are held together by hydrogen bonds between purine base of one STRAND and pyrimidine base of the other and vice versa. Because of different sizes and geometries of the bases the only POSSIBLE pairing in DNA and G (GUANINE ) and C (cytosine) through three H-bonds,i.e., `(C-=G)` and between A (adenine) and T (thymine) through two H-bonds (i.e., A =T). Due to this base -pairing principle, the sequence of bases in one strand automatically fixes the sequence of bases in the other strand . THUS , the two strands are complementary and not IDENTICAL.
Discussion
11207.

The volume of the reaction vessel containing an equilibrium mixture in the reaction , SO_2Cl_2(g) hArr SO_2(g) + Cl_2(g) is increased. When equilibrium is reestablished:

Answer»

The AMOUNT `SO_2`(G) will decrease
The amount of `SO_2Cl_2`(g) will increase
The amount of `Cl_2`(g) will increase
The amount of `Cl_2` (g) will REMAIN unchanged

Answer :C
Discussion
11208.

Which of the following monomer gives the polymer neoprene on polymerisation?

Answer»

`CCl_(2)=CCl_(2)`
`CH_(2)=CHCl`
`CH_(2)=C(CL)-CH=CH_(2)`
`CF_(2)=CF_(2)`

Answer :C
Discussion
11209.

Write the rate expression for the following reactions, assuming them as elementary reaction . (i) 3A+5B_2rarr4CD (ii) X_2+Y_2rarr2XY

Answer»

SOLUTION :(i) `3A+5B_2rarr4CD `
RATE `=-1/3(DELTA[A])/(DT)=-1/5(Delta[B_2])/(dt)=+1/4(Delta[CD])/(dt)`
(ii) `x_2+y_2rarr2XY`
Rate `=-(Delta[X_2])/(dt)=-(Delta[Y_2])/(dt)=+1/2(Delta[XY])/(dt)`
Discussion
11210.

Which of the following values in electron volt per atom represent the first ionisation enthalpy of oxygen and nitrogen respectively?

Answer»

14.6,13.6
13.6, 14.6
13.6, 13.6
14.6, 14.6

Answer :B
Discussion
11211.

What happens when chlorine gas is passed through cold caustic soda ?

Answer»

SOLUTION :`Cl_2 + 2NAOH RARR NACL + NACLO + H_2O`
Discussion
11212.

Which of the following does not give alkane

Answer»

REACTION of `CH_3I` with Na in ether
Reaction of sodium acetate with sodalime
Electrolysis of concentrated sodium acetate solution
Reaction of ETHYL chloride with alc. KOH

Solution :`CH_3-CH_2-Cl+underset"(alc.)""KOH"to underset"Ethene"(CH_2=CH_2)+KCl+H_2O`
In presence of alc. KOH DEHYDROHALOGENATION occur and ALKENE is formed
Discussion
11213.

The volume occupied by 0.2 mole of methane at N.T.P. is :

Answer»

4.48 L
8.96 L
4.4 L
2.24 L

SOLUTION :1 mole of METHANE at N.T.P. OCCUPIES= 22.4 L
0.2 mole of methane at N.T.P occupies
` = 22.4 XX 0.2 = 4.48 L`
Discussion
11214.

The Van't Hoff factor for calcium nitrate (Ca(NO_(3))_(2) is 2.5 . Using the dissociation equilibrium, Ca(NO_(3))_(2) hArr Ca^(2+)+2NO_(3)^(-) the degree of dissociation is :

Answer»

0.25
0.33
0.66
0.75

Solution :`CA(NO_(3))_(2) hArr Ca^(2+)+2NO_(3)^(-)`
If a is the degree of dissociation,
`1-alpha "" alpha""2ALPHA`
Total no. of particles after dissociation
`=1-alpha+alpha+2alpha=1+2alpha`
Van.t HOFF factor `=(1+2 alpha)/(1)=2.5`
`:.2 alpha=1.5`or`alpha=(1.5)/(2)=0.75`
Discussion
11215.

Which of the following compound does not gives benzoic acid on oxidation

Answer»




ANSWER :D
Discussion
11216.

Which causes water pollution

Answer»

2.4-D and pesticides
Smoke
Automobile exhaust
Aeroplanes

Solution :Herbicides (e.g.2,4-D,2,4,5-T) , INSECTICIDES (e.g. DDT, aldrin , BHC) and rodenticides CAUSES water POLLUTION
Discussion
11217.

What mass of calcium oxide will be obtained by heating 3 mol of CaCO_3.

Answer»


ANSWER :238.5 G
Discussion
11218.

Which of the following plot obeys the Raoult's law for all concentration ?

Answer»




SOLUTION : If the solution obeys Raolult's law for all CONCENTRATION its vapour PRESSURE would vary inearly from zero to the vapour pressure of pure SOLVENT.
Discussion
11219.

Which of the following set of polymers contains same monomer which is used to prepare urotropine on reaction with NH_(3)?

Answer»

GLYPTAL, UREA -FORMALDEHYDE RESIN, Nylon-6,6
Glyptal, urea-formaldehyde resin, melamine-formaldehyde resin
Nylon-6, urea formaldehyde resin, melamine-formaldehyde resin
Nylon-6, glyptal, Nylon-6,6

Answer :B
Discussion
11220.

What are the values of A and B in Debye Huckel and Onsagar equation?

Answer»

Solution :Debye Huckel and Onsagar equation is
Where `A = (82.4)/(sqrt(DT)eta)`
`B = (8.20 xx 10^5)/(3sqrt(DT))`
D = DIELECTRIC constant of the MEDIUM
`eta` = Viscosity of the medium
T = TEMPERATURE in Kelvin.
Discussion
11221.

Which is known as purple of cassius ?

Answer»

Colloidal silver solution
Colloidal GOLD solution
Aqueous solution of SOAP
`As_2S_3` colloidal solution

ANSWER :B
Discussion
11222.

Unlike phenols, alcohols are easily protonated. Or Alcohols are easily protonated in comparison to phenols. Or Why do phenolsnot give protonation reactions readily?

Answer»

SOLUTION :In phenols, the LONE PAIRS of electrons on the oxygen atom are delocalised over the benzene ring due to reosonance and HENCE are not easily available for protonation. In contrast, in alcohols, the lone pairs of electrons on the oxygen atom are localized due to absence of resonacne and hence are easily available for protonation.
Discussion
11223.

What is the IUPAC name of compound when carbonyl carbon atom is attached to phenyl group and ethyl group

Answer»

propanonebenzene
1-phenylpropan-1-one
2-phenylpropan -1-one
propiophenone

Answer :B
Discussion
11224.

Which of the following acts as "activator" in the foth flotation process?

Answer»

KCN
NaCN
Sodium ETHYL Xanthalate
COPPER sulphate

Answer :4
Discussion
11225.

Which amino acid is optically inactive ?

Answer»

GLYCINE
PROLINE
ALANINE
PHENYL alanine

SOLUTION :Glycine
Discussion
11226.

Which of the following is a hypotic drug?

Answer»

LUMINAL
Salol
Piperazine
Novalgin

Solution :Luminal is a hypontic DRUG SINCE it INDUCES SLEEP.
Discussion
11227.

Which statement is incorrect for catalyst ?

Answer»

It does not affect the equilibrium constant. 
It increases the PROPORTION of products in less time. 
It decreases the activation ENERGY of a reaction. 
It increases the free energy change for the reaction. 

SOLUTION :It increases the free energy change for the reaction.
CATALYST not change the free energy change for the reaction.
Discussion
11228.

What does the part'6,6' mean in the name nylon-6,6 ?

Answer»

Solution :It means that both the monomers used in condensation POLYMERIZATION leading to the FORMATION of nylon-6, 6 CONTAIN SIX CARBONS, each.
Discussion
11229.

Which of the following xenon compound has the same number of lone pairs as in I_(3)^(-)? (near central atom)

Answer»

`XeO_(4)`
`XeF_(4)`
`XeF_(2)`
`XeO_(3)`

Answer :C
Discussion
11230.

Which of the following is oxidised to form ethyl methyl ketone ?

Answer»

2-propanol
2-butanol
1-butanol
1-propanol

Solution :`CH_3CHOHC_2H_5 OVERSET"OXIDATION"to CH_3COC_2H_5`
Discussion
11231.

What is molecular geometry of XeO_3 ?

Answer»

SOLUTION :TRIGONAL PLANAR
Discussion
11232.

Which of the following is a polysaccharide ?Maltose, Sucrose, Fructose, Cellulose

Answer»

Maltose
Sucrose
Fructose
Cellulose

Answer :D
Discussion
11233.

Which is a characteristic of catalyst used in a chemical reaction ?

Answer»

Decreases rate constant of the REACTION
Increase ACTIVATION energy of the reaction
Reduces enthalpy of the reaction
Does not AFFECT EQUILIBRIUM constant of reaction

ANSWER :D
Discussion
11234.

Which of the following properties of liquids does not decrease with rise in temperature ?

Answer»

1. Vapour pressure
2. Viscosity
3. SURFACE tension
4. DENSITY

Answer :A
Discussion
11235.

Which one of the following is the most acidic compound ?

Answer»




SOLUTION :I EFFECT DECREASES the ACIDIC NATURE
Acidic nature
Discussion
11236.

Which of the following is not true? In acidic medium K_(2)Cr_(2)O_(7) oxidises:

Answer»

BROMIDES to bromine
HYDROGEN sulphide to SULPHURIC acid
ferrous SALTS to FERRIC salts
iodides to iodine

Answer :B
Discussion
11237.

Which of the following is a polyamide?

Answer»

Bakelite
Terylene
Nylon-6, 6
Tetlon

Solution :Nylon-6, 6 is a GENERAL NAME for all SYNTHETIC fibresforming POLYAMIDES
Discussion
11238.

The value of Delta_(f)G^(@) for formation Cr_(2)O_(3) is -540 kJ mol^(-1) and that of Al_(2)O_(3) is -827 kJ mol^(-1). Is the reduction of Cr_(2)O_(3) possible with aluminium?

Answer»

Solution :The two equations are :
`(4)/(3)Al_((s))+O_(2(g))rarr(2)/(3)Al_(2)O_(3(s))`
`Delta_(f)G^(@)=-827kJmol^(-1)""...(i)`
`(4)/(3)Cr_((s))+O_(2(g))rarr(2)/(3)Cr_(2)O_(3(s))`
`Delta_(f)G^(@)=-540kJmol^(-1)""...(II)`
Subtracting equation (ii) from equation (i), we get
`(4)/(3)AL(s)+(2)/(3)Cr_(2)O_(3)(s)rarr(2)/(3)Al_(2)O_(3)(s)+(4)/(3)Cr(s)`,
`Delta_(f)G^(@)=-287kJmol^(-1)`
As `Delta_(f)G^(@)` of the combined redox REACTION is negative, therefore, reduction of `Cr_(2)O_(3)` by Al is possible.
Discussion
11239.

Which of the following is most reactive towards nucleophilic substitution reaction ?

Answer»

`CH_(2)=CH-CL`
`C_(6)H_(5)Cl`
`CH_(3)CH=CHCL`
`ClCH_(2)-CH=CH_(2)`

SOLUTION :ALLYL chloride `(ClCH_(2)CH=CH_(2))` is more reactive than VINYL `(CH_(2)=CHCl, CH_(3)CH=CHCl)` and aryl `(C_(6)H_(5)Cl)` chlorides.
Discussion
11240.

Which product is formed when is treated with concentrated KOH solution ?

Answer»

.
.
.
.

ANSWER :B
Discussion
11241.

Tonics, generally contains,

Answer»

ether
methanol
ETHANOL
rectified SPIRIT

Answer :C
Discussion
11242.

Which of the following is most reactive towards electrophilic nitration ?

Answer»

Toluene
BENZENE
Benzoic acid
Nitrobenzene.

Solution :DUE to `+ I` effect of `CH_(3)` in toluene, it is more reactive than benzene. Due to electron withdrawing NATURE of `-COOH` group in benzoic acid (C) and `-NO_(2)` group in nitrobenzene (D), both (C) and (D) are LESS reactive than benzene.
Discussion
11243.

Which of the following gives H_(2) on cathode and O_(2) on anode on electrolysis by using platinum electrode ?

Answer»

Molten NaCl
Dilute solution of NaCl
Concentration solution of NaCl
Solid NaCl.

Solution :Electrolysis of dilute solution of NaCl is actually electrolysis of WATER only. So on reduction of water `H_(2)` gas liberated on cathode and `O_(2)` gas liberated on anode.
On anode: `H_(2)O_((l)) to 2H_((aq))^(+)+(1)/(2)O_(2(g))`. . . (Oxidation)
`underline("On cathode : "2H_(2)O_((l))+2e^(-) to H_(2(g))+2OH_((aq))^(-) . . . ."(Reduction)")`
`3H_(2)O_((l)) to UNDERSET("NEAR cathode")(H_(2(g))+underset("Near anode")((1)/(2))O_(2(g))+(2H_(aq))^(+)+2OH_((aq))^(-))`
Discussion
11244.

The stability of the carbonium ion depends upon :A:the polarity of the group to which it is attachedB:the inductive effect of the attached group

Answer»

A is CORRECT
B is correct
Both A & B are correct
none of these

Answer :C
Discussion
11245.

Which one of the following schemes of ordering closed packed sheets of equal sized spheres do not generate close packed lattice?

Answer»

ABCABC
ABACABAC
ABBAABBA
ABCBCABCBC

Answer :C
Discussion
11246.

Write the main product(s) in each of the following reactions : (i) CH_(3)-overset(CH_(3))overset("|")underset(CH_(3))underset("|")"C "-O-CH_(3)+Hirarr (ii) CH_(3)-CH=CH_(2)overset((i)B_(2)H_(6))underset((ii)3H_(2)O_(2)//OH^(-))rarr (iii) C_(6)H_(5)-OH overset((i)aq. NaOH)underset((ii)CO_(2), H^(+))rarr

Answer»

Solution :(i) `CH_(3)-overset(CH_(3))overset("|")underset(CH_(3))underset("|")"C "-O-CH_(3)+HI rarr underset("alcohol")underset("Methyl")(CH_(3)OH)+underset("t-Butyl IODIDE")(H_(3)-overset(CH_(3))overset("|")underset(CH_(3))underset("|")"C "-I)`
(ii) `CH_(3)-CH=CH_(2)overset((i)B_(2)H_(6))underset((ii)3H_(2)O_(2)//OH^(-))rarrunderset("Propan-1-ol")(CH_(3)CH_(2)CH_(2)OH)`
Discussion
11247.

Which of the following complex is heteroleptic type?

Answer»

`[Cr(CO_(3))(NO)_(2)]`
`NA[Co(CO)_(4)]`
`PT[(NH_(3))_(4)Cl_(2)]Cl_(2)`
(a) and (c) both

Answer :D
Discussion
11248.

What is the minimum concentration of SO_(4)^(2-) required to precipitate BaSO_(4) in a solution containing 1.0 xx 10^(-4) mol Ba^(2+) (K_(sp) for BaSO_(4) is 4 xx 10^(-10))

Answer»

`4 xx 10^(-10)M`
`2 xx 10^(-7)M`
`4 xx 10^(-6)M`
`2 xx 10^(-3) M`

SOLUTION :`BaSO_(4) hArr BA^(2+) + SO_(4)^(2-)`
`K_(sp) = S^(2)rArr S = SQRT(K_(sp)) , K_(sp) = [Ba^(2+)] xx [SO_(4)^(2-)]`
`4 xx 10^(-10) = [1 xx 10^(-4)] xx [SO_(4)^(2-)]`
`[SO_(4)^(2-)] = (4 xx 10^(-10))/(1 xx 10^(4)) = 4 xx 10^(-6)`.
Discussion
11249.

Which of the following reagent is not used to prepare alkyl halides from alcohols ?

Answer»

`Br_(2)//C Cl_(4)`<BR>RED `P+Br_(2)`
`NaBr//H_(2)SO_(4)`
`KI+H_(3)PO_(4)`

ANSWER :A
Discussion
11250.

Which of the following comparisons of the average kinetic energy and the average molecular speeds of H_(2) and N_(2) gases at 300K is correct ?

Answer»

`{:("AVERAGE K.E.","Average molecular SPEED"),(H_(2) = N_(2),H_(2)=N_(2)):}`
`{:("Average K.E.","Average molecular speed"),(H_(2) lt N_(2),H_(2)gtN_(2)):}`
`{:("Average K.E.","Average molecular speed"),(H_(2) = N_(2),H_(2)ltN_(2)):}`
`{:("Average K.E.","Average molecular speed"),(H_(2) = N_(2),H_(2)gtN_(2)):}`

SOLUTION :Average K.E. `= ( 3)/(2) RT`
`:.` Average K.E. `H_(2) =N_(2)`
Average molecular speed, `mu_(av) = sqrt(( 8 RT)/( pi M ))` or `mu_(av)prop sqrt((1)/( M ))`
`:.` Average molecular speed of `H_(2) GT N_(2)`
Discussion