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84901.

Aldehydes are oxidised to acids by

Answer»

potassium dicromate
Tollen's reacgent
Fehling's solution
all of these

Solution :We know that ALDEHYDE can be oxidised with potassium dicromate `(K_(2)Cr_(2)O_(7))` in ACIDIC medium to form carboxylic acid, when TOLLENS reagent is used to OXIDISE an aldehyde, the silver ion is reduced to metallic from if the reaction is carried out in a clean test tube . We also know that when Fehling's solution is used to oxidise an aldehyde, the complexe cupric ion is reduced to cuprous oxide.
Therefore all of these options are correct.
84902.

Addition of water to ethyne in the presence of H_2SO_4 and HgSO_4 gives

Answer»

Acetone
Acetaldehyde
Formaldehyde
Glyoxal

Answer :B
84903.

Addition of water to alkynes occurs in acidic medium and in the presence of Hg^(2+) ions as a catalyst. Which of the following products will be formed on addition of water to but-1-yne under these conditions ?

Answer»

`CH_(3)-CH_(2)-CH_(2)-OVERSET(O)overset("||")C-H`
`CH_(3)-CH_(2)-overset(O)overset("||")C-CH_(3)`
`CH_(3)-CH_(2)-overset(O)overset("||")C-OH+CO_(2)`
`CH_(3)-overset(O)overset("||")C-OH+H-overset(O)overset("||")C-H`

Answer :B
84904.

Aldehydes are obtained by the catalytic dehydrogenation of _____

Answer»

SOLUTION :PRIMARY ALCOHOLS
84905.

Aldehydes are isomeric with

Answer»

Ketones
Ethers
Alcohols
Fatty acids

Answer :A
84906.

Addition of water to alkynes occurs in acidic medium and in the presence of Hg^(2+) ions as a catalyst. Which of the following products will be formed on addition of water to but-1-yne under these conditions.

Answer»

`CH_(3)-CH_(2)-CH_(2)-OVERSET(O)overset(||)(C)-H`
`CH_(3)-CH_(2)-overset(O)overset(||)(C)-CH_(3)`
`CH_(3)-CH_(2)-overset(O)overset(||)(C)-OH+CO_(2)`
`CH_(3)-overset(O)overset(||)(C)-OH+H-overset(O)overset(||)(C)-H`

Solution :`CH_(3)CH_(2)C-=CH overset(H^(+)//H_(2)O,Hg^(2+))toCH_(3)CH_(2)-CO-CH_(3)`.
84907.

Addition of water across the double bond of an alkene is presence of sulphuric acid giving follows _______ rule.

Answer»

MARKOWNIKOFF's
ANTI Markownikoff
Sayt zeff's
Swern

ANSWER :A
84908.

Aldehydes are generally more reactive than ketones towards nucleophillic addition reactions. Give two reasons.

Answer»

SOLUTION :(a) STERIC EFFECT
(B) ELECTRONIC effect.
84909.

Addition of water to acetylenic compounds is catalysed by______and ______.

Answer»

SOLUTION :`HgSO_(4),` DIL `H_(2)SO_(4)`.
84910.

Aldehydes are generally more reactive than ketones towards nucleophilic addition reactions .anytwo reasons.

Answer»

SOLUTION :(a) STERIC EFFECT(B) ELECTRONIC effect .
84911.

Addition of to the aqueous hydrolysis of benzyl chloride dose not increase the rate of the hydrolysis but change only the composition of the final products. This indicates that the reaction is proceeding through

Answer»

`S_N1` MECHANISMS
`S_N1` mechanisms
`S_E1` mechanisms
`S_E2` mechanisms

Solution :RATE is depenendingonly on ONE reactant . iodination of benzene is a REVERSIBLE REACTION
84912.

Addition of solution of oxalate to an aqueous solution of mixture of Ba^(2+), Sr^(2+) and Ca^(2+) will precipitate :

Answer»

`CA^(2+)`
`Ca^(2+)` and `SR^(2+)`
`Ba^(2+)` and `Sr^(2+)`
All the three

Solution :Oxalates of these metals are INSOLUTION
84913.

Aldehydes are first oxidation product of :

Answer»

PRIMARY alcohals
secondry alcohals
TERTIARY alcohals
MONOHYDRIC alcohals

ANSWER :A
84914.

Additionof sulphurmonochlorideto ethene gives :

Answer»

ETHYL SULPHIDE
Epoxyethane
Mustardgas
GLYCOL

ANSWER :C
84915.

Aldehydes are first oxidation product of:

Answer»

PRIMARY alcohols
Secondary alcohols
Tertiary alcohols
Dihydric alcohols

Answer :A
84916.

Addition of solution of oxalate to an aqueous solution of mixture of Ba^(++),Sr^(++) and Ca^(++) will precipitate

Answer»

`Ca^(++)`
`Ca^(++) and Sr^(++)`
`BA^(++) and Sr^(++)`
All the three

Solution :Oxalate of these METALS are insoluble.
84917.

Aldehydes are easily oxidisable yet propanal can conveniently br prepared by the oxidation of propanol by acid K_(2)Cr_(2)O_(7).

Answer»

Solution :Aldehydes having boiling points less than 373 K can be REMOVED by DISTILLATION therefore propanol can easily be PREPARED from propanol by distillation from the ALCOHOL acid DICHROMATE solution.
84918.

Addition of sodium thiousulphate solution to a solution of silver nitrate give 'X'as white precipitate, insoluble in water but soluble in excess thiosulphate solution to give 'Y'. On boiling in water, 'Y' gives 'Z'. 'X','Y' and 'Z'. respectively, are

Answer»

`Ag_2S_2O_3,Na_3[AG(S_2O_3)_2],Ag_2S`
`Ag_2SO_4,Na[Ag(S_2O_3)_2],Ag_2S_2`
`Ag_2S_2O_3, Na_5[Ag(S_2O_3)_3], AGS`
`Ag_2SO_3,Na_3[Ag(S_2O_3)_2],Ag_2O`

SOLUTION :
84919.

Aldehydesare characterised by the general formula

Answer»

`C_(N)H_(2n)O`
`C_(n)H_(2n)`
`C_(n)H_(2n+)OH`
`C_(n)H_(2n+2)O`

Answer :A
84920.

Addition of sodium hydrogen sulphite does not take place in

Answer»

`(AAK_MCP_37_NEET_CHE_E37_026_A01)`

ANSWER :C
84921.

Addition of sodium chloride to a saturated solution of silver chloride.

Answer»

DISSOCIATION of `AGCI` increases
concentration of `CI^-` decreases
dissociation of `AgCI^-` decreases
concentration of `AG^+` increases

Answer :C
84922.

Addition of SnCl_2 to HgCl_(2) gives ppt.

Answer»

White TURNING to red
White turning to GREY
Black turning to white
None of these

Solution :Even `SnCl_(2)` ADDED into `HgCl_(2)` solution to GIVE white grey COLOUR.
84923.

Addition of SnCl_(2) to HgCI_(2) gives ppt. :

Answer»

WHITE turning to GREY
Black turning to white
white turning to red
None of these

Solution :`HgCI_(2)` formed is whitewhich later on turns to HG grey due to father reduction
84924.

Aldehydes and ketones will not form crystalline derivatives with

Answer»

<P>sodium bisulphite
phenylhydrazine
semicarbazide hydrochloride
dihydrogen sodium phosphate.

Solution :Dihydrogen sodium phosphate `(NaH_(2)PO_(4))` does not have a lone PAIR of electrons on the P atom. As such it can not act as NUCLEOPHILE and hence does not react with aldehydes and ketones.
84925.

Addition ofone equivalent of bromine to 1,3-pentadiene produces:

Answer»

4, 5 dibromo-2-pentene
1, 4-dibromo-2-pentene
3, 4-dibromopentene
3, 4-dibromo-2-pentene

Answer :D
84926.

Aldehydes and ketones undergo nucleophilic addition reactions. With weak nucleophiles such as ammonia and its derivatives, (H_2 N-Z), aldehydes and ketones react in weakly acidic medium to form compounds containing carbonnitrogen double bond with the elimination of water to form . Aldehydes can be easily oxidised to carboxylic acid on treatment with common oxidising agents like KMnO_4 K_2 Cr_2 O_7 , HNO_3, etc. The carboxylic acid formed contain the same number of carbon atoms as the aldehydes. However ketones under drastic conditions with powerful oxidising agents undergo cleavage of C-C bond giving mixture of carboxylic acids having lesser number of C atoms than the original ketone.Name the product obtained when pentan-2-one is oxidised with conc. HNO_3

Answer»

SOLUTION :`UNDERSET("Popoff.srule ")(CH_3CH_2CH_2 - underset(O )underset(|| ) C-CH_3 OVERSET("CONC"HNO_3) toCH_3 CH_2COOH +CH_3 COOH `
84927.

Addition of one drop of HNO_(3) in group (III)qanalysis is to (a) _____.

Answer»


ANSWER :a. OXIDISE `FE^(2+) to Fe^(3+)`
84928.

Aldehydes and Ketones reacts with NH_2OH to form Aldoximes and Ketoximes respectively.Configuration of these can be determined by Beckmann rearrangement as that group migrates which is anti w.r.t-OH It is interesting to note that the migration of group is completely retentive and no loss of optical activity is seen. CH_3CHO+NH_2OHoverset(Delta)toPoverset(H^(o+))toQoverset(Br_2//KOH)toR(CH_3NH_2) (as only product) Following is correct

Answer»

<P>Oxime P is syn form of geometrical isomers
Oxime P is anti form
Q is more basic than R
Q is `H-undersetunderset(O)(||)C-NH-CH_3`

Solution :`CH_3-undersetunderset(O)(||)C-H+H_2N-OHtounderset((P))(CH_3-CH=N-OH("anti"))tounderset((Q))(CH_3-undersetunderset(O)(||)C-NH_2)OVERSET("Heffmann Bromamide")toCH_3-NH_2`
84929.

Aldehydes and ketones undergo reactions due to the presence of alpha-hydrogen atom. Write the name of the reaction of aldehyde which takes place only because of the presence of alpha-hydrogen atom.

Answer»


ANSWER :ALDOL CONDENSATION
84930.

Addition of NH_4Cl to NH_4OH results in :

Answer»

INCREASES in `OH^-` concentration
Decreases in `OH^-` concentration
No CHANGE in `OH^-` concentration
None of these

Answer :B
84931.

Aldehydes and Ketones reacts with NH_2OH to form Aldoximes and Ketoximes respectively.Configuration of these can be determined by Beckmann rearrangement as that group migrates which is anti w.r.t-OH It is interesting to note that the migration of group is completely retentive and no loss of optical activity is seen. Following is true about product

Answer»

It is also (+) laevorotatory
Both (+) and (-) forms are obtained in equal amount
It is having 'S' configuration for CHIRAL carbon
it is having R configuration for chiral carbon

Solution :SHIFT is retentive therefore INITIAL configuration will be maintained. Initially It is "S" and afterwards it will be "R" due to change in PRIORITY of atoms.
84932.

Addition of O_2 on ethylene in presenceof Ag at 200^@C forms:

Answer»

EPOXY ethane
Oxiranes
Cyclic ethers
All of these

Answer :C
84933.

Aldehydes and Ketones reacts with NH_2OH to form Aldoximes and Ketoximes respectively.Configuration of these can be determined by Beckmann rearrangement as that group migrates which is anti w.r.t-OH It is interesting to note that the migration of group is completely retentive and no loss of optical activity is seen.

Answer»




SOLUTION :
84934.

Aldehydes and ketones react with oine molecule of analcohol to form compounds called hemiacetals, in which there is one hydroyl group and one either-like group. Reaction of a hemiacetal with a second molecule of alcohol gives an acetal and a molecule of water. We study this reaction Draw structural formulas for the hemicetal and acetal formed from these reagents. The stoichiometry of each reaction is given in the problem. Product Q is

Answer»




ANSWER :B
84935.

If NaOH is added to an aqueous solution of Zn^(2+) ions, a white precipitate appears and on adding access NaOH, the precipitate dissolves. In this solution zinc exists in the:

Answer»

CATIONIC part
Anionic part
Both (a) and (B)
None

Answer :B
84936.

On addition of mineral acid to an aqueous solution of Borax, the following compound is formed

Answer»

Boron hydride
Pyroboric acid
Metaboric acid
Orthoboric acid

Solution :Orthoboric acid is formed when an aqueous solution of borax is treated with HYDROCHLORIC or sulphuric acid.
`Na_(2)B_(4)O_(2) + 2HCl + 5H_(2)O to4H_(3)BO_(3) + 2NaCl`
`Na_(2)B_(4)O_(7)+ H_(2)SO_(4) + 5H_(2)O to4H_(3)BO_(3) + Na_(2)SO_(4)`
84937.

Aldehydes and ketones may be distinguished by using

Answer»

saturated solution of `NaHSO_3`
2:4 dinitrophenylhydrazine
Tollen's reagent
BAEYER's reagent

Solution :Aldehydes , being reducing agents , reduce Tollen's reagent (am. `AgNO_3`) to produce a MIRROR to free silver. Ketones are not reducing agents and do not react with Tollen's reagent. With the REAGENTS (a) and (b) both aldehydes and ketones react to give insoluble crystalline derivatives. With (d) neither the aldehydes nor the ketones react.
84938.

Aldehydes and ketones have high boiling point as compared to hydrocarbons and ethers of comparable molecular mass and less than that of alcohols. Give reason.

Answer»

Solution : Aldehydes and ketones have high boiling point as COMPARED to hydrocarbons and ethers of COMPARABLE molecular MASS. It is due to the WEAK molecular association in aldehyde and ketone arising out of the dipole-dipole interactions .

These dipole-dipole interactions are weaker than intermolecular H-bonding. The boiling points of aldehydes and ketones are much lower than those of CORRESPONDING alcohols and carboxylic acids which possess inter molecular hydrogen bonding.
84939.

Addition of mercuric acetate in the presence of water is called as oxymercuration.The adduct obtained gives alcohol on reduction with NaBH_4 in alkaline medium.This is known as demercuration.Oxymercuration demercuration allows Markownikoff's addition of H, OH without rearrangement.The net result is the addition of H_2O Answer the following question : Product 'A'is :

Answer»




SOLUTION :
84940.

Aldehydes and ketones have boiling points lower than those of ___and higher than those of_____of comparable masses.

Answer»

SOLUTION :ALCOHOLS, ALKANES
84941.

Addition of mercuric acetate in the presence of water is called as oxymercuration.The adduct obtained gives alcohol on reduction with NaBH_4 in alkaline medium.This is known as demercuration.Oxymercuration demercuration allows Markownikoff's addition of H, OH without rearrangement.The net result is the addition of H_2O Answer the following question :

Answer»

ENOL FORMATION
`S_N 1` mechanism
Neighbouring GROUP particitation
SNAr mechanism

Solution :
84942.

Addition of mercuric acetate in the presence of water is called as oxymercuration.The adduct obtained gives alcohol on reduction with NaBH_4 in alkaline medium.This is known as demercuration.Oxymercuration demercuration allows Markownikoff's addition of H, OH without rearrangement.The net result is the addition of H_2O Answer the following question : CH_3-undersetunderset(CH_3)(|)oversetoverset(CH_3)(|)(C)-CH=CH_2underset((ii)CH_3OH NaBH_4NaOH)overset((i)Hg(OAc)_2.THF)toAoverset(Hi(Conc.))toBProduct B is :

Answer»


SOLUTION :
84943.

Aldehydes and ketones give addition reactions with

Answer»

HCN
`NaHSO_3`
`CH_3MgX`
All of these

Answer :D
84944.

Addition of KI toHgI_2 forms complex K_2[HgI_4] having……

Answer»

YELLOW colour
Blue colour
Violet colour
Colourless nature

Answer :D
84945.

Aldehydes and ketones give

Answer»

ELECTROPHILIC reaction
Electrophilic ADDITION reaction
Nucleophilic addition reactions.
Nucleophilic SUBSTITUTION reaction.

Answer :C
84946.

Addition of KI to a solution of copper sulphate gives :

Answer»

`CuI_2`
`Cul_2^(2+)`
`Cu_2I + I`
`CUL + I_2`

ANSWER :C
84947.

Aldehydes and ketones form hydrocarbons by -

Answer»

PHENYL hydrazine
Hydrazine
Semicarbazide
Hydrogen cyanide

Answer :D
84948.

What happens when Potassium iodide solution is added to an aqueous solution of copper sulphate. Give equation.

Answer»

`CuI_2`
`Cul_2^(2+)`
`Cu_2I + I`
`CUL + I_2`

ANSWER :C
84949.

Aldehydes and ketones both give addition reaction with

Answer»

PHENYL hydrazine
Hydrazine
Semicarbazide
Hydrogen cyanide

Answer :D
84950.

Addition of FeCl_3 solution toK_4[Fe(CN)_6] solution gives :

Answer»

Ferro-ferricyanide
Ferri-ferrocyanide
Ferri-ferricyanide
NONE

ANSWER :B