94420 + Interview Questions in Chemistry in Class 12 Page 437 InterviewSolution

21801.	The total number of Aldols (beta- Hydroxy carbonyl compounds) are formed in the following reaction. (Ignore stereoisomers) PhCHO+CH_(3)CH=O+Ph-underset(O)underset(\|\|)(C)-CH_(3) overset(Dil.NaOH.Delta) (rarr)
Answer» SOLUTION :`PhCHO+CH_(3)CH=O+Ph-underset(O)underset(\|\|) (C)-CH_(3) overset(DilNaOH,Delta)(rarr)` TOTAL `6` aldol PRODUCTS

Discussion

21802.	Which onc of the following salts will have the same value of van't Hoff factor (i) as that of K_(4)[Fe(CN)_(6)].
Answer» `Al_(2)(SO_(4))_(3)` `NaCl` `AL(NO_(3)) _(3)` `Na_(2) SO_(4)` Solution :`K _(4)[Fe(CN) _(6)] and Al _(2) (SO _(4)) _(3)` both dissociates to GIVE 5 ions or `i=5` `K_(4)[Fe(CN)_(6)] HARR 4K^(+) + [Fe (CN)_(6) ] ^(4-)` and ` Al_(2) (SO_(4)) _(3) hArr 2Al ^(3**) . 2SO _(4) `

Discussion

21803.	What is chemotherapy ?
Answer» SOLUTION :USEOF CHEMICALS fortherapetic effectis calledchemotherapy.

Discussion

21804.	When chloroform is heated with aniline and caustic potash, we get a compound having:
Answer» ROSE odour Jasmine odour Bitter ALMOND odour Obnoxious odour Answer :D

Discussion

21805.	Which of the follow2ing show the oxidation state of +4 ?
Answer» PM EU Sm Tb ANSWER :D

Discussion

21806.	Under the same reaction conditions, initial concentration of 1.386" mol dm"^(-3) of a substance becomes half in 40 seconds and 20 seconds through first order and zero order kinetics respectively. Ratio (k_(1)//k_(0)) of the rate constants for first order (k_(1)) and zero order (k_(0)) of the reactions is
Answer» `0.5" mol"^(-1)" dm"^(3)` `1.0" mol dm"^(-3)` `1.5" mol dm"^(-3)` `2.0" mol"^(-1)" dm"^(3)` Solution :For 1ST order reaction, `t_(1//2) = (0693)/(K) or k_(1) = (0.0693)/(t_(1//2)) = (0693)/(40S)` For zero order reaction, `t_(1//2) = ([A]_(0))/(2K) or k_(0) = ([A]_(0))/(2t_(1//2)) = (1386 mol dm^(-3))/(2xx 20s)` `therefore (k_(1))/(k_(0)) = (0693)/(40s) xx (2xx 20s)/(1386 mol dm^(-3)) = 05 mol^(-1) dm^(3)`

Discussion

21807.	Which of the following rate laws has an overall order of 0.5 for the reaction A + B + C rarr product?
Answer» `K[A][B][C]^(0.5)` `k[A]^(0.5)[B]^(0.5)[C]^(0.5)` `k[A]^(1.5)[B]^(-1)[C]^(0)` `k[A][B]^(0)[C]^(0.5)` Solution :Order of reaction = 1.5 – 1 + 0 = 0.5

Discussion

21808.	Which of the following alkyl halides is hydrolysed by S_(N^(1)) mechanism?
Answer» `CH_(3)Cl` `CH_(3)CH_(2)Cl` `CH_(3)CH_(2)CH_(2)Cl` `(CH_(3))_(3)"CCL"` ANSWER :D

Discussion

21809.	What is wrong about the following pair of compounds? [Cr(H_(2)O)_(6)]Cl_(3)and[Cr(H_(2)O)_(5)Cl]Cl_(2).H_(2)O
Answer» They are HYDRATION isomers They have DIFFERENT colours Their 0.1M aqueous solutions have same molar conductivity They have different IUPAC name Answer :C

Discussion

21810.	What is the product formed when 3, 3-dimethyl-1-butene is hydrated by dil H_2SO_4 and the product is subsequently boiled with water?
Answer» SOLUTION :

Discussion

21811.	Which of the following is used in petroleum refining and refining of vegetable oils?
Answer» CHARCOAL SILICA GEL Permutit Nickel SOLUTION : Silica gel

Discussion

21812.	The solution of nickel sulphate in which nickel rod is dipped is diluted 10 times. The halfcell potential of nickel:
Answer» Decreases by 60 MV Increases by 30 m V Decreases by 30 m V Decreases by 60 V Answer :C

Discussion

21813.	When an acid solution of oxalic acid at 80^(@)C is titrated with KMnO_(4) solution, the first few drops of KMnO_(4) are decoloured slowly but decolourisation occurs fast later. This is because
Answer» Of increases in the concentration of `CO_(2)` formed Oneof the products `Mn^(+2)` ACTS as auto catalyst Both `Mn^(+2)` and `K^(+)` IONS act auto catalyst `KMnO_(4)` catalyses the reaction at the later STAGES Answer :B

Discussion

21814.	What is a biodegradable polymer? Give an example of a biodegradable aliphatic polymer.
Answer» Solution :Biodegradable polymers are the polymers which get degraded by the environmental process and do not cause accumulation of SOLID waste materials. These polymers contain functionalgroups similar to the functional groups present in biopolymers. POLY `beta` -hydroxybutyrate CO`Beta` -HYDROXY valerate (PHBV) is an EXAMPLE of biodegradable polymer.

Discussion

21815.	Which of the following is an isomer of diethyl ether ?
Answer» `(C_2H_5)_2CHOH` `C_3H_7OH` `(CH_3)_3COH` `(CH_3)_2CHOH` ANSWER :C

Discussion

21816.	Which of the following options are correct ?
Answer» CAST iron is obtained by remelting PIG iron with scrap iron and coke using hot air blast. In extraction of silver, silver is extracted as cationic complex. Nickel is purified by zone refining. Zr and Ti are purified by VAN Arkel method. Solution :are both CORRECT options.

Discussion

21817.	The salts AgX, AgY and AgZ are all equally soluble in water (andnone are very soluble at all). When each saltis added to separate beakers of 100mL of 1.0M HNO_(3), you notice that AgY is much more soluble than AgZ in acid. The salt AgX is no more soluble in strong acid than it is in water. Which of the following best explains this?
Answer» `HX, HY` and `HZ` are all WEAK acids `HX` is a weak ACID and `HY` and `HZ` are STRONG acids `HY` and `HZ` are weak acids and `HX` is a strong acid, `HY` is a stronger acid than `HZ` `HY` and `HZ` are weak acids and `HX` is a strong acid `HZ` is a stronger acid than `HY` Answer :D

Discussion

21818.	Why are cimetidine and ranitidine better antacids than sodium hydrogen carbonate or magnesium or aluminium hydroxide ?
Answer» Solution :Sodium hydrogen carbonate or magnesium or aluminium hydroxide neutralize the excess HCl and raise the pH to an appropriate level in stomach THEREFORE, these and control only the moms and not the cause. In CONTRAST, cimetidine and ranitidine are BETTER antacids because they prevent the INTERACTION of histamine with the receptor present in the stomach wall and thus release lesser AMOUNT of HCl

Discussion

21819.	Which of following will not conduct electricity?
Answer» KOH (AQ.) FUSED NaCl Solid KCl Graphite Answer :C

Discussion

21820.	The sigma_(2s) orbital has a higher energy than sigma_(1s)^() orbital, sigma(_2s) orbital is bonding while sigma_(1s)^() orbital is antibonding because :
Answer» `sigma_(2s)` is PLANAR while `sigma_(1s)^()` orbital. `sigma_(2s)` is symmetrical while `sigma_(1s)^()` is UNSYMMETRICAL `sigma_(2s)` is nearer to the NUCLEI than `sigma_(1s)^(**)` none of these ANSWER :D

Discussion

21821.	Which of the following is a branched chain polysaccharide?
Answer» CELLULOSE RAFFINOSE AMYLOSE Glycogen Answer :D

Discussion

21822.	Which does not react with chlorine in dark
Answer» `C_2H_4` `C_2H_2` `CH_4` `CH_3CHO` ANSWER :C

Discussion

21823.	Which of the following statements regarding the manufacture of H_2SO_4by contact process is not true?
Answer» sulphur is BURNT in AIR to form `SO_2` `SO_2` is catalytically oxidised to `SO_3` `SO_3`is dissolved in water to get 100% sulphuric acid ` H_2SO_4`obtained by contact process is of HIGHER purity than that obtained by lead CHAMBER process. Solution :In contact process, `SO_3` is dissolved in `H_2SO_4`to get `H_2S_2O_7`(oleum).

Discussion

21824.	Which ion is not coloured:
Answer» `CU^+` `Cr^2+` `Co^2+` `Cr^3+` ANSWER :A

Discussion

21825.	What is the role of ZnCl_(2) in dry cell ?
Answer» SOLUTION :`ZnCl_(2)` combines with the `NH_(3)` produced to form a COMPLEX salt `[ZN(NH_(3) )_(2) ]Cl_(2)` .

Discussion

21826.	Which of the following statement(s) is//are incorrect for cyclooctatraene?
Answer» Cyclooctatetraene has all eight C - C BONDS equal in length. It is non-planar It has 8N electrons. The molecule is antiaromatic. Solution :Non - aromatic (tub-shaped) due to non-planarity. No EFFECTIVE DELOCALISATION.

Discussion

21827.	Which of the following pair of EAN of central metal atom is not same?
Answer» `[Fe(CN)_(6)]^(3-) and [Fe(NH_(3))_(6)]^(3+)` `[CR(NH_(3))_(6)]^(3+) and [Cr(CN)_(6)]^(3-)` `[FeF_(6)]^(3-) and [Fe(CN_(6))]^(3-)` `[Ni(CO)_(4)] and [Ni(CN)_(4)]^(2-)` Answer :D

Discussion

21828.	Which one of the following complexes has highest magnetic moment value ?
Answer» `[FE(CN)_6]^(3-)` `[Co(CN)_6]^(3-)` `[Fe(H_2O)_6]^(3+)` `[CoF_6]^(3-)` Answer :C

Discussion

21829.	Which of the following Grignard reagent is suitable for the preparation of 3-methyl-2-butanol?
Answer» 2-Butanone+methylmagnesium bromide Acetone+ethylmagnesium bromide Acetaldehyde+isoproplmagnesium bromide Ethyl propionate+methylmagnesium bromide Solution :

Discussion

21830.	Which of the following statements is not true regarding (+)- lactose ?
Answer» `(+)` -Lactose , `C_12H_(22)O_(11)` contains `8OH` groups On hydrolysis `(+)`- lactose gives equal amounts of `D-(+)`-glucose and `D-(+)` -GALACTOSE. `(+)` - Lactose is a `beta`-glycoside formed by the union of a molecule of `D(+)` glucose and a molecule of `D(+)`- galactose `(+)`-Lactose is a reducing sugar and does not exhibit MUTAROTATION Solution :`(+)` -Lactose is a reducing sugar and HENCE shows mutarotation.

Discussion

21831.	Which of the following complexes would have minimum [Ag^(+)] concentration in solution ?
Answer» `[AG(NH_(3))_(2)]^(+)` `[Ag(S_(2)O_(3))_(2)]^(3-)` `[Ag(CN)_(2)]^(-)` All have EQUAL `[Ag^(+)]` SOLUTION :`[Ag(CN)_(2)]^(-)` is more stable.

Discussion

21832.	Tollen's reagent is not reduced by ……………………
Answer» `ALPHA`-D- GLUCOSIDE LACTOSE Glucose Maltose SOLUTION :`alpha`-D- Glucoside

Discussion

21833.	What class of drugs is used in sleeping pills?
Answer» SOLUTION :The NEUROLOGICALLY active drugs. 1, TRANQUILIZERS (barbiturates) is used in SLEEPING pills.

Discussion

21834.	Which of the followinghas asymmetric carbon atom
Answer» `CH_(2)-Cl-CH_(2)-BR` `CH_(3)CH(COOH)CH_(2)CH_(3)` `CH_(3)CHCl_(3)` `CH_(3)CHO` ANSWER :B

Discussion

21835.	WhycannotVitamin C be storedin our body?
Answer» SOLUTION :VITAMIN C is watersoluble ,thereforeit isreadilyexcretedin urineand hencecannotbe storedin the BODY .

Discussion

21836.	Which order is correct for the decreasing reactivity to monobromination of the following compounds ? C_(6)H_(5)CH_(3) (I),""C_(6)H_(5)COOH (II), ""C_(6)H_(6) (III), ""C_(6)H_(5)NO_(2)(IV)
Answer» `I GT II gt III gt IV` `I gt III gt II gt IV` `II gt III gt IV gt I` `III gt I gt II gt IV` ANSWER :C

Discussion

21837.	Which of the following statements is (are) true ?
Answer» The evaporation of water is an endothermic CHANGE The CONVERSION of white phosphorus to red phosphorus is an exothermic reaction The heat of neutralisation of a strong acid with a strong BASE is always the same `Delta H`is negative for endothermic reactions Answer :A::B::C

Discussion

21838.	Which of the following reactions is not correct according to the law of conservation of mass.
Answer» `2Mg(s)+O_(2)(G) rarr 2MgO(s)` `C_(3)H_(8)(g)+O_(2)(g) rarr CO_(2)(g)+H_(2)O(g)` `P_(4)(s)+5O_(2)(g) rarr P_(4)O_(10)(s)` `CH_(4)(g)+2O_(2)(g) rarr CO_(2)(g) +2H_(2)O(g)` SOLUTION :EQN. (b) is not balanced and hence is not correct.

Discussion

21839.	Write the monomers used for getting the following polymers: Polyvinyl chloride
Answer» SOLUTION :VINYL CHLORIDE, `CH_2=CHCl`

Discussion

21840.	Which of the following statement (s) is//are true about ozone?
Answer» It is a PALE BLUR gas at room temperature It oxidises S and P evolving oxygen gas It oxidises `SnCl_(2)//HCL` and `SO_(2)` evolving oxygen gas It reacts with `BaO_(2) and H_(2)O_(2)` evolving oxygen gas Answer :A::B::D

Discussion

21841.	Which of the following is not an oxide ore ?
Answer» Magnettite Zincite Cuprite Siderite Answer :D

Discussion

21842.	Which one of the following does not decolourise an acidified KMnO_4 solution?
Answer» `SO_2` `FeCl_3` `H_2O_2` `FeSO_4` ANSWER :B

Discussion

21843.	Whichof thefollowingalkyl halideis usedasa methylatingagent ?
Answer» `CH_(3)l` `C_(2)H_(5)Br` `C_(2)H_(5)CL` `C_(6)H_(5)Cl` Answer :A

Discussion

21844.	Which of the following type of substances can be permanently magnetised?
Answer» Diamagnetic Ferromagnetic Ferrimagnetic Antif erromagnetic Answer :B

Discussion

21845.	The word 'molecule' was first introduced by :
Answer» Dalton Bohr Avogadro Rutherford Answer :C

Discussion

21846.	The time for half of a first order reaction is l hr. What is the time taken for 87.5% completion of the reaction:
Answer» 1 hour 2 hour 3 hour 4 hour Answer :C

Discussion

21847.	The surface tension of several alcohols at 20°C is gamma(CH_(3)OH)= 22.61 "dyne" cm^(-1), gamma(C_(2)H_(5)OH) = 2.275 xx 10^(-2) Nm^(-1)and gamma(n-C_(3)H_(7)OH) = 23.7 mJ m^(-2).The alcohol having the highest surface tension is:
Answer» `CH_(3)OH` `C_(2)H_(5)OH` `n-C_(3)H_(7)OH` All same Answer :C

Discussion

21848.	Which of the following react(s) with nitrous acid ?
Answer» NITROETHANE 2-Nitropropane Phenol Ethylamine Solution :AMINES can react with `HNO_(2)` & Phenols

Discussion

21849.	What is "Chirality" ?
Answer» Solution :The PROPERTYOF an OBJECT and its MIRROR image being nonsuper IMPOSABLE is .Chirality..

Discussion

21850.	Which of the following is an example of homogeneous catalysis ?
Answer» Oxidation of `NH_(3)` in Ostwald's process Oxidation of `SO_(2)` in CONTACT process Oxidation of `SO_(2)` in LEAD chamber process Manufacture of `NH_(3)` by Haber's process Solution :(c) : Homogeneous catalysis is the one in which reactant and CATALYST form the single phase. In oxidation of `SO_(2)`, gaseous `NO_(2)` is used as catalyst, both form the same phase during the REACTION.

Discussion

Explore topic-wise InterviewSolutions in .

The total number of Aldols (beta- Hydroxy carbonyl compounds) are formed in the following reaction. (Ignore stereoisomers) PhCHO+CH_(3)CH=O+Ph-underset(O)underset(||)(C)-CH_(3) overset(Dil.NaOH.Delta) (rarr)

Which onc of the following salts will have the same value of van't Hoff factor (i) as that of K_(4)[Fe(CN)_(6)].

What is chemotherapy ?

When chloroform is heated with aniline and caustic potash, we get a compound having:

Which of the follow2ing show the oxidation state of +4 ?

Which of the following rate laws has an overall order of 0.5 for the reaction A + B + C rarr product?

Which of the following alkyl halides is hydrolysed by S_(N^(1)) mechanism?

What is wrong about the following pair of compounds? [Cr(H_(2)O)_(6)]Cl_(3)and[Cr(H_(2)O)_(5)Cl]Cl_(2).H_(2)O

What is the product formed when 3, 3-dimethyl-1-butene is hydrated by dil H_2SO_4 and the product is subsequently boiled with water?

Which of the following is used in petroleum refining and refining of vegetable oils?

The solution of nickel sulphate in which nickel rod is dipped is diluted 10 times. The halfcell potential of nickel:

When an acid solution of oxalic acid at 80^(@)C is titrated with KMnO_(4) solution, the first few drops of KMnO_(4) are decoloured slowly but decolourisation occurs fast later. This is because

What is a biodegradable polymer? Give an example of a biodegradable aliphatic polymer.

Which of the following is an isomer of diethyl ether ?

Which of the following options are correct ?

Why are cimetidine and ranitidine better antacids than sodium hydrogen carbonate or magnesium or aluminium hydroxide ?

Which of following will not conduct electricity?

The sigma_(2s) orbital has a higher energy than sigma_(1s)^(**) orbital, sigma(_2s) orbital is bonding while sigma_(1s)^(**) orbital is antibonding because :

Which of the following is a branched chain polysaccharide?

Which does not react with chlorine in dark

Which of the following statements regarding the manufacture of H_2SO_4by contact process is not true?

Which ion is not coloured:

What is the role of ZnCl_(2) in dry cell ?

Which of the following statement(s) is//are incorrect for cyclooctatraene?

Which of the following pair of EAN of central metal atom is not same?

Which one of the following complexes has highest magnetic moment value ?

Which of the following Grignard reagent is suitable for the preparation of 3-methyl-2-butanol?

Which of the following statements is not true regarding (+)- lactose ?

Which of the following complexes would have minimum [Ag^(+)] concentration in solution ?

Tollen's reagent is not reduced by ……………………

What class of drugs is used in sleeping pills?

Which of the followinghas asymmetric carbon atom

WhycannotVitamin C be storedin our body?

Which order is correct for the decreasing reactivity to monobromination of the following compounds ? C_(6)H_(5)CH_(3) (I),""C_(6)H_(5)COOH (II), ""C_(6)H_(6) (III), ""C_(6)H_(5)NO_(2)(IV)

Which of the following statements is (are) true ?

Which of the following reactions is not correct according to the law of conservation of mass.

Write the monomers used for getting the following polymers: Polyvinyl chloride

Which of the following statement (s) is//are true about ozone?

Which of the following is not an oxide ore ?

Which one of the following does not decolourise an acidified KMnO_4 solution?

Whichof thefollowingalkyl halideis usedasa methylatingagent ?

Which of the following type of substances can be permanently magnetised?

The word 'molecule' was first introduced by :

The time for half of a first order reaction is l hr. What is the time taken for 87.5% completion of the reaction:

The surface tension of several alcohols at 20°C is gamma(CH_(3)OH)= 22.61 "dyne" cm^(-1), gamma(C_(2)H_(5)OH) = 2.275 xx 10^(-2) Nm^(-1)and gamma(n-C_(3)H_(7)OH) = 23.7 mJ m^(-2).The alcohol having the highest surface tension is:

Which of the following react(s) with nitrous acid ?

What is "Chirality" ?

Which of the following is an example of homogeneous catalysis ?

The sigma_(2s) orbital has a higher energy than sigma_(1s)^() orbital, sigma(_2s) orbital is bonding while sigma_(1s)^() orbital is antibonding because :