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14851.

Write the balanced chemical equation involved in the manufacture of potassium- dichromate from chromite ore.

Answer»

SOLUTION :`4FeCr_(2)O_(4) + gNa_2CO_3 + 7O_(2) to 8Na_2CrO_4 + 2Fe_2O_3 + 8CO_2`
`2Na_2CrO_4 + 2H^(+) to Na_2Cr_2O_(7) + H_2O + 2Na^(+)`
`Na_2Cr_2O_(7) + 2KCl to K_2Cr_2O_(7) + 2NaCl`.
Discussion
14852.

When CH_(3)COCH_(3) reacts with CI_(2) and NaOH, which of the following is formed

Answer»

`CHCI_(3)`
`C CI_(4)`
`C CI_(2)H_(2)`
`CH_(3)CI`

Solution :`2CH_(3)COCH_(3)+CI_(2)//NAOH rarr 2CHCI_(3) + 2CH_(3)COONA+ HCI`
Discussion
14853.

Write names of two greenhouse gases.

Answer»

SOLUTION : CARBON DIOXIDE and METHANE,
Discussion
14854.

The reagent(s) for the following conversion is/are

Answer»

alc. KOH
alc. KOH FOLLOWED by `NaNH_(2)`
AQ. KOH followed by `NaNH_(2)`
`Zn//CH_(3)OH`

Answer :B
Discussion
14855.

Which of the following complex ions is expected to absorb visible light ? [At. No. Zn = 30, Sc = 21, Ti = 22, Cr = 24]

Answer»

`[Ti(en)_(2)(NH_(3))_(2)]^(4+)`
`[Cr(NH_(3))_(6)]^(3+)`
`[ZN(NH_(3))_(6)]^(2+)`
`[Sc(H_(2)O)_(3)(NH_(3))_(3)]^(3+)`

Solution :`d^(0)(Ti^(4+), Sc^(3+))` and `d^(10)(Zn^(2+))`species will not absorb VISIBLE light and are COLOURLESS whereas `d^(3)(Cr^(3+))` can undergo d-d transition on absorption of visible light of a particular wavelength and will be coloured.
Discussion
14856.

Which of the following has most acidic hydrogen ?

Answer»

Hexan-3-one
Hexan-2,4-dione
Hexana-2,5-dione
Hexan-2,3-dione ?

Solution :Hexan-2,4-dione has the most acidic hydrogen because the carbanion LEFT after RELEASE of `H^(+)` ION gets RESONANCE stablished as follows :
Discussion
14857.

What do you understand by activation of adsorbent? How is it achieved ?

Answer»

Solution :Adsorption capacity of adsorbent can be increased by activation of adsorbent. Adsorbent can be more activated by the following REACTION.
(i) Amount of adsorption is increased by increasing surface area of adsorbent. For that adsorbent is CONVERTED into small particles or powder FORM.
(ii) Adsorbent can be activated by some specific reactions too. e.g. To more activate the coal made from wood it should be heated in air at 600K to 1330K temperature. ABSORBED gases are removed by doing this and the space obtained to enter the new ADSORBATE.
Discussion
14858.

What is the IUPAC name of the product obtained from oxidation of phenol ?

Answer»

1, 4 - BENZOQUINONE
1, 2 - Benzo Catechol
Cyclohexa - 2, 5 diene 1, 4 - dione
None of these

Solution : 1, 4 - Benzoquinone
Discussion
14859.

The solubility in water of sulphate down the Be group is Be gt Mg gt Ca gt Sr gt Ba.

Answer»

HIGH heat of SOLVATION for smaller ions like `Be^(2+)`
Increasing molecular weight
Decreasing lattice energy
INCREASES in melting points

Solution :The hydration energy decreases from `Be^(+2)` to `BA^(+2)`. This causes the decreases in the solubilities of the sulphates in this ORDER. In other words, the solubilities decreases with increases in the ionic size.
Discussion
14860.

Which one of the following is not a colloidal solution?

Answer»

SMOKE
INK
AIR
coffee

Solution : air
Discussion
14861.

The values of van der Waals' constant 'a' for the gases O_(2). N_(2) , NH_(3) and CH_(4) are 1.360, 1.390 , 4.170 and 2.52 L^(2) atm mol^(-2) respectively . The gas which can most easily be liquified is :

Answer»

`O_(2)`
`N_(2)`
`NH_(3)`
`CH_(4)`

ANSWER :C
Discussion
14862.

When Cu^(2+) is treated with KI, a white precipitate is formed. Explain the reaction with the help of chemical equation.

Answer»

Solution :Reduction of `CU^(2+)` to `Cu^(+)` takes place due to reaction with `I^(-)` ions. This is given by the EQUATION
`2Cu^(2+)+41^(-)to UNDERSET("White PPT")(Cu_(2)I_(2))+I_(2)`
Discussion
14863.

Which of the following state are correct

Answer»

BENZYL HALIDES are more REACTIVE than vinly and anyl halides
vinyl/halides are more reactive than alkylhalides
Aryl halides are LESS reactive than alkylhalide
Aryl halides are more reactive than benzyl halides

Answer :A::C
Discussion
14864.

What is magnetic character of F_2 ?

Answer»

SOLUTION :DIAMAGNETIC
Discussion
14865.

The relation between equivalent condutance and the specific conductance is given as ............. .

Answer»

SOLUTION :`LAMBDA=(k^(x)10^(-3))/(N)`
Discussion
14866.

Yellow ppt of (a)_____ isformedwhen CoCI_(2) reactswith excess of KNO_(2) in presence of CH_(3)COOH.

Answer»


ANSWER :a.`K_(3)[CU(NO_(2))_(6)]`
Discussion
14867.

Which of the following element has maximum electron gain enthapy(negative)?F,Cl,Br,I.

Answer»

F
Cl
Br
I

Answer :B
Discussion
14868.

When Cl_(2) gas is passed intoa mixturecontaining Br^(Θ) and I^(Θ) and CHCI_(3),I_(2) (voilet ) firstappear CHCI_(3) layer.

Answer»


Solution :Reducingpower of `I^(Theta) gt BI^(Theta) GTCI^(Theta) gt I^(Theta)`
`21^(Theta) + CI_(2) RARR 2CI^(Theta) + I_(2)`
`2Hi^(Theta) + CI_(2) rarr 2CI^(Theta) + Bi_(2)`
Thus `I_(2)` is FORMED in precipitate of `Bi_(2)` andgiven violetcolour in `CHCI_(2)` hencetrue
Discussion
14869.

What is amorphous solid ?

Answer»

Solution :In amorphous solids,the ARRANGEMENT of constituent PARTICLES has only SHORT RANGE order.
Discussion
14870.

What is the ratio of t_(1//2) to t_(1//3)for a first-order reaction?

Answer»


ANSWER :1.71
Discussion
14871.

Which of the following is polysulphide rubber

Answer»

Glyptal
thiokol
Buna-N
Neo-prene

ANSWER :B
Discussion
14872.

When benzamide is treated with bromine and alkali gives compound A. Also when benzamide is reduced by LiAlH_4, compound B is formed. Find A and B. Write the equations.

Answer»

Solution :(i) When benzamide react with bromine and ALKALI, Hoffmann reaction TAKE place and aniline `C_6H_5NH_2` is formed as (A).
`{:(C_6H_5CONH_2 overset(Br_2"/"KOH)(to)C_6H_5NH_2+CO_2),(" BenzamideAniline(A) "):}`
(ii) When Benzamide is reduced by `LiAlH_4`, Benzylamine `C_6H_5CH_2NH_2` is formed as (B).
`{:(C_6H_5CONH_2 UNDERSET(4[H]) overset(Br_2"/"KOH)(to)C_6H_5NH_2+H_2O),("Benzylamine(B)"):}`.
Discussion
14873.

[X]+H_2SO_4 to [Y] a colourless gas with irritating smell. [Y]+K_2Cr_2O_7+H_2SO_4 to Green solution [X] and [Y] are :

Answer»

`SO_(3)^(2-)`, `SO_2`
`Cl^(-), HCl `
`S^(2-), H_2S`
`CO_3^(2-), CO_2 `

Solution :`SO_3^(2-) + H_2SO_4 to UNDERSET("Burning smell of sulphur (IRRITATING)")(SO_2 UARR + SO_4^(2-)) + H_2O`
`SO_2` turns `K_2Cr_2O_7` solution in ACID medium GREEN .
Discussion
14874.

What is the ratio of uncomplexed to complexed Zn^(2+) ion in a solution that is 10 M in NH_(3), if the stability constant of [Zn(NH_(3))_(4)]^(2+) is 3XX10^(9) ?

Answer»

`3.3xx10^(-9)`
`3.3xx10^(-11)`
`3.3xx10^(-14)`
`3xx10^(-13)`

SOLUTION :`3xx10^(9)=([Zn(NH_(3))_(4)^(2+)])/([Zn^(2+)])xx(1)/(10^(4))`
`IMPLIES ([Zn^(2+)])/([Zn(NH_(3))_(4)^(2+)])=3.3xx10^(-14)`
Discussion
14875.

Which of the following is not suitable for chemisorption ?

Answer»

It is irreversible. 
It is multimolecular. 
Depends upon NATURE of GAS. 
There is no noticeable EFFECT of change in temperature. 

Solution :It is multimolecular.
Discussion
14876.

Which of the following does not undergo benzoin condensation?

Answer»

Benzene carbaldehyde
p-Toluene carbaldehye
Phenyl ethanal
n-Methoxy benzaldehyde.

Solution :Phenylethanal `(C_(6)H_(5)CH_(2)CHO)` has no CHO group directly ATTACHED to phenyl group i.e., it is not an aromatic aldehyde.
Discussion
14877.

Which of the following alkyl halides has the maximum density ?

Answer»

`C_3H_7I`
`C_2H_5I`
`CH_3Br`
`CH_3I`

ANSWER :A
Discussion
14878.

The structure of 2-methyl-1-propanol is _________.

Answer»

`CH_(3)-UNDERSET(CH_(3))underset(|)CH-CH_(2)OH`
`CH_(3)-CH_(2)-underset(CH_(3))underset(|)H-OH`
`CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)C-OH`
`CH_(3)-underset(OH)underset(|)overset(H)overset(|)C-H_(3)`

Answer :A
Discussion
14879.

Vanadium pentoxide is coloured. Why?

Answer»

Solution :Oxidation state of V in `_(2)O_(5)` is `+5`. It has do configuration, but COLOURED. The COLOUR arises due to defects in crystal structure of `V_(2)O_(5)`, is SOLID state.
Discussion
14880.

Which one of the following is used in the manufacture of tyrecards fabrics?

Answer»

NYLON 6, 6
nylon 6
orlon
dacron

Solution :nylon 6
Discussion
14881.

underset(hv)overset(Cl_(2))rarr A mixture of all isomers possible from the mono-chlorination the structures is subjected to fractional distillation, then how many fractions will be obtaine

Answer»

2
3
4
5

Solution :N//A
Discussion
14882.

The standard oxidation potential values of A,B,C and D are -0.03 V, +0.108 V , _0.07 Vand +0.1 V respectively. This spontaneous cell reaction takes place between __________.

Answer»

A and B
B and D
D and A
B and C

Answer :D
Discussion
14883.

Which of the following is a acetyl derivative of morphine ?

Answer»

HEROIN
CODEINE
Phenacetine
Analgin

SOLUTION :Heroin is DIACETYL morphine
Discussion
14884.

Which of the following defects is also known as dislocation defect?

Answer»

FRENKEL DEFECT 
SCHOTTKY defect 
Non-stoichiometric defect 
Simple INTERSTITIAL defect 

Solution :In Frenkel defects cations are dislocated from its LATTICE sites and occupy intersticial sites.
Discussion
14885.

Which of the following given applications of O_3 gas is not correct?

Answer»

It is USED as a GERMICIDE, disinfectent and for sterilising water
It is used as a bleaching agent for oils, IVORY and delicate fabrics
It is used as an oxidising agent in the manufacture of potassium permanganate
It is used in oxyacetylene and OXYHYDROGEN flames

Answer :D
Discussion
14886.

What happens when PCl_(5) is heated?

Answer»

SOLUTION :`PCl_(5)` has three EQUATORIAL (202 PM long) and two axial (240 pm long) bonds. Since axial bonds are weaker than equatorial bonds, therefore, when `PCl_(5)` is heated, the less stable axial bonds breaks to form `PCl_(3)`.
`PCl_(5) overset("HEAT")RARR PCl_(3)+Cl_(2)`.
Discussion
14887.

Which of the following compounds increases BOD value of water supply

Answer»

`CO_(2)`
`O_(3)`
`H_(2)O`
`C_(2)H_(5)OH`

ANSWER :D
Discussion
14888.

Which one of the following is used to test ketones?

Answer»

IODOFORM TEST
Tollen's REAGENT test
FEHLING's SOLUTION test
Benedict's solution test

Solution :Iodoform test
Discussion
14889.

Which oxidising agent used in Etard's-reaction ?

Answer»

SOLUTION :`CrO_2Cl_2` or CHROMYL CHLORIDE
Discussion
14890.

To arrive at the molecular formula and at the structural formula the different steps involved are (a) Qualitative analysis, (b) Quantitative analysis In the qualitative analysis the different steps involved are (a) Extra element detection (b) Functional group analysis In the quantitative analysis the percentage of every element is determined and then the emperical and molecular formulae are determined. Both these are followed bystructural elucidation. Which of the following reagents can be used to identify benzene in on go?

Answer»

Bromine WATER test
`CHCl_(3)+AlCl_(3)` (anhydrous) test
`I_(2)+NaOH`
No test is available

Solution :All ARENES give orange to red colour upon treatment with CHLOROFORM and anhydrous aluminium chloride. These are due to the formation of triaryl methyl carbocation which is formed by Friedal-Crafts REACTION by a transferred of `H^(-)` ion i.e.,

Napththalence `to` BLUE colour
Anthracene `to` green colour
PHenanthrene `to` purple colour
Hence choice (b) is correct.
(a) is incorrect. Benzene does not show `Br_(2)` water test as it does undergo addition reaction.
(c) is wrong. Benzene does not show iodoform test nor any reaction with `I_(2)+NaOH`
Discussion
14891.

Write the structures and names of the compounds formed when compound 'A' with molecular formula, C_(7)H_(8) is treated with Cl_2 in the presence of FeCl_(3).

Answer»

Solution :Compound with MF `C_(7)H_(8)` is toluene. Since `CH_(3)` group is o, p-directing, therefore, CHLORINATION of toluene with `Cl_(2)` in presence of `FeCl_(3)` GIVES a MIXTURE of o-chlorotoluene and p-chlorotoluene, in which the p-isomer predominates.
Discussion
14892.

To arrive at the molecular formula and at the structural formula the different steps involved are (a) Qualitative analysis, (b) Quantitative analysis In the qualitative analysis the different steps involved are (a) Extra element detection (b) Functional group analysis In the quantitative analysis the percentage of every element is determined and then the emperical and molecular formulae are determined. Both these are followed bystructural elucidation. The number of -OH groups in a compound not containing any other functional group can be determined by

Answer»

`CH_(3)COCl`
`CH_()MgBr`
`CH_(3)OCH_(3)`
Both (a) and (b)

SOLUTION :The number of `-OH` groups in compound can be esitmated by subtracting the molecular mass of reactant from the molecular MAS of product and dividing by 42.
Or by estimating the volule of `CH_(4)` liberated after heating the compound with excess of `CH_(3)MgBr`. If one mole of organic compound gives one mole of `CH_(4)` then it CONTAINS one `OH` group. If one mole of organic compound gives `n` MOLES of `CH_(4)` then there ae `nOH` groups. The Grignard method and `CH_(3)COCl` method can be used only if `-OH` groups is present in the compound. Hence (d) is correct while (c) is wrong.
Discussion
14893.

The reducing nature of hydrides of groupP 10 elements vary as

Answer»

`H_(2)Po GT H_(2)Te gt H_(2)Se gt H_(2)S TGT H_(2)O`
`H_(2)O gt H_(2)S gt H_(2)Se gt H_(2)Te tgt H_(2)Po`
`H_(2)S gt H_(2)Se gt H_(2)Te gt H_(2)O tgt H_(2)Po`
`H_(2)O gt H_(2)Po gt H_(2)Te gt H_(2)Se tgt H_(2)S`

Answer :A
Discussion
14894.

The solubility product of a sparingly soluble salt AX_(2) is 3.2 xx 10^(-11). Its solubility (in moles/litres) is

Answer»

`2 XX 10^(-4)`
`4 xx 10^(-4)`
`5.6 xx 10^(-6)`
`3.1 xx 10^(-4)`

SOLUTION :`AX_(2) rarr UNDERSET(x)(A) + underset(2X)(2X)`
`K_(sp) = 4 x^(3), x = 3sqrt((3.2 xx 10^(-11))/(4)), x = 2 xx 10^(-4)` mole/litre
Discussion
14895.

What is secondary structure of proteins?

Answer»

SOLUTION :Secondary structure of proteins INVOLVES folding of polypeptide chain forming intramolecular and intermolecular HYDROGEN bonding. There are two secondary structures : `alpha`-helix and `BETA` -PLEATED structures
Discussion
14896.

To arrive at the molecular formula and at the structural formula the different steps involved are (a) Qualitative analysis, (b) Quantitative analysis In the qualitative analysis the different steps involved are (a) Extra element detection (b) Functional group analysis In the quantitative analysis the percentage of every element is determined and then the emperical and molecular formulae are determined. Both these are followed bystructural elucidation. Which of the following tests will phloroglucinol give?

Answer»

`NaHCO_(3)` test
Iodoform test
Oxime test with `NH_(2)OH`
Cerric AMMONIUM nitrate test

Solution :Phloroglucinol will show oxime test as phloroglucinol shows tautomerisum.

HENCE CHOICE (c) correct
(a) is wrong. Phenolic groups are not that highly acidic to show sodium bicarbonic test.
(b) is wrong. Though phloroglucinol has hyperconjugative `H`- atoms in the KETO form, they are onluy 2 in number so cannot form iodoform. (d) is wrong. Only allphatic `-OH` groups will show ceric ammonium nitrate test.
Discussion
14897.

Which of the following contains acetic acid ?

Answer»

Vinegar
Molasses
Coal tar
Butter.

Answer :A
Discussion
14898.

Which of the following is globular proteins ?

Answer»

ENZYMES
Keratin
Fibroin
ALBUMIN

SOLUTION :Enzymes
Discussion
14899.

Write the name of the electrolyte used in fuel cell.

Answer»

SOLUTION :CONCENTRATED AQUEOUS KOH solution.
Discussion
14900.

Which of the following are correct

Answer»



PROUDUCT A is FORMED by aromatic nucleophilic SUBSTITUTION reaction
Product B is formed by HOFMANN's bromamide reaction

Solution :
Discussion