AS_CHEMISTRY

Friday 12 August 2022

Haloalkanes & Haloarenes II

Part I deals with RX & chloroform

Part 2 deals with ArX & Dihalides + Properties of chloroform.

1. No precipitate is formed when chloroform reacts with …..This is because; being covalent CHCl3 can’t furnish Cl-1 ions

A) AgNO3

B) AgNO2

C) Blue Litmus

D) H2SO4

2. CHCl3 discovered by J.V.Liebig & named by J.B.Dumes. It’s anaesthetic nature was discovered by James Young. It is not used in

manufacture of …..directly

A) Chloropicrin

B) Phosgene

C) Chloretone

D) Salicylic Acid

3. CCl4 + 2HF=> CF2Cl2 + 2HCl .

The name of Freon formed is

A) Freon -12

B) Freon-11

C) Freon -10

D) NOTA

4. CH3-CHBr2 +2 KCN=> X ; X+ H20/H+ => Y ; Y on Heating gives …..by losing …..

A) Propanoic acid , CO2

B) Propanoic anhydride , H20

C) Propanoic acid , CO2

D) Propan-1,3-doic acid , CO2 , H2O

5. Which of the following is not suitable method for formation of Haloarenes?

A) From Benzene diazonium Chloride Or

Sandmeyer’s reaction

B) Gattermann Halogenation reaction

C) From rxn of Benzene + HCl + ½ O2

(commercially or Raschig Method)

D) From reaction Phenol with NaCl

6. Which of the statement is correct:-

A) In Sandmeyer’s reaction Cu shuttles from +1 to +2 state & source of X is from CuX

B) In Gattermann reaction Cu shuttles from 0 to +1 & source of X is HX.

C) Florobenzene is prepared via Balz-Schiemann reaction

D) Iodobenzene is prepared by reaction of BD salts with KI & warming the mixture

E) All of the Above

7. Identify the reaction that involves

Isocynanide test or test for 1o

amines

A) Phenol + CHCl3 + Aq.KOH => Salicyaldehyde

B) Phenol + CCl4 + Aq. KOH => Salicylic acid

C) Ph-NH2 + CHCl3 + KOH => Ph-NC + KCl + H2O

D) NOTA

8. DDT is formed by reaction of ------& ----- in presence of Conc. Sulphuric acid

A) 1,1,1-trichloroethanal & Chlorobenzene

B) Chloropicrin & Chlorobenzene

C) Phosgene & Chlorobenzene

D) NOTA

9. Perflorocarbons(PFCs) have general formula

A) CnF2n+2

B) CnH2n+2

C) CnCl2n+F

D) NOTA

10. The pesticide DDT slowly changes to

A) p,p’-dichlorodiphenyldichloroethene

B) p,p’-dichlorodiphenyldichloroethane

C) p,p’-dichlorodiphenylethene

D) CCl3-CHO & Chlorobenzene

11. Toluene when treated with Br2 & Fe , gives p-bromotoluene as the main product , because the methyl group

A) Is O/P directing group & EDW

B) is meta-directing group

C) Activates ring by hyperconjugation

D) Deactivates ring by of the above

1) A, C. 2) A,B,C 3) A,B 4) A only

12. ArX are less reactive towards SN reactions as compared to RX due to

A) Formation of less stable carbonium ion

B) Resonance stabilization

C) Longer C-X bond

D) I-effect

E) Sp2 Hybd. C attached to X

1) A,B,C 2) B,D,E 3)B,E D) D,E

13. Which of the following is most reactive towards SN reactions

A) 2,4,6-Trinitrochlorobenzene

B) 2,4-Dinitrochlorobenzene

C) P-nitrochlorobenzene

D) m-nitrochlorobenzene

14. The Electrophile source used in Friedal craft Acylation of Haloarenes is

A) RCOCl

B) (RCO)2O & RCOCl

C) RCl

D) All of the Above

15. Step I- CH3CH2-OH + Cl2 => CH3CHO

Step II- CH3CHO + 3Cl =>CCl3-CHO

In above reaction, the role of Cl2 in step I & II respectively is

A) Oxid. & Chlorination

B) Red. & chlorination

C) Oxid. & Hydrolysis

D) Chlorination

16. O-Methoxybromobenzene is treated with NaNH2 & then with NH3. The product formed is

A) O-Methoxyaniline

B) Aniline

C) Methoxybenzene

D) m-methoxyaniline

For Print / screenshot

Monday 8 August 2022

Haloalkanes MCQs-Part I

Haloalkanes MCQ's For NEET Series -I

1. In the displacement rxn. RI + MF => RF +MI. The rxn will be most favourable if M happens to be

A) Li

B) Na

C) K

D) Rb

2. The major product formed when 2Methylbut-1-ene reacts with HBr?

A) 2-Bromo-3-methylbutane

B) 2-Methyl-3-bromobutane

C) 2-Bromo-2methylbutane

D) NOTA

3. 1,4-dimethylcyclohexane on chlorination gives ---monochorination products

A) 1

B) 5

C) 3

D) NOTA

4. Which of the following is correct statement

A) Reactivity order of Halides for dehydro- halogenation is RI>RBr>RCl>RF

B) Reactivity order of Halogens & alkanes for halogenations of alkanes F2>Cl2>Br2>I2 & t>s>p respectively

C) Reactivity order of Alcohols & HX in reaction of ROH with HX is – t>s>p & HI>HBr>HCl respectively

D) All of the Above

5. Which of the following compound is not chiral ?

A) CH₃CHDCH₂Cl

B) 2-Butanol

C) 2-Hydroxypropanoic acid

D) DCH₂CH₂CH₂Cl

6. Ethylchloride is converted into diethylether by

A) Groove’s reaction

B) Tilden Reagent

C) Grignard reaction

D) Williamson’s synthesis

7. Consider the reactions

I) (CH₃)₂CH-CH₂Br + C₂H₅-OH => (CH₃)₂CH-CH₂OC₂H₅ + HBr

II) (CH₃)₂CH-CH₂Br + C₂H₅O^- => (CH₃)₂CH-CH₂-O-C₂H₅+ Br^-

The mechanism of rxn (I) & (II) are respt.

A) SN1 & SN2 B) SN1 & SN1

C) SN2 & SN2 D) SN2 & SN1

8.Which one of the following is most reactive towards SN1 rxn?

A) C₆H₅CH(C₆H₅)Br

B) C₆H₅CH(CH₃)Br

C) C₆H₅C(CH₃) (C₆H₅)Br

D) C₆H₅CH₂Br

9. What is IUPAC name of Westrosol( Cl₂C=CHCl) & Westron( CHCl₂-CHCl₂) respectively

A) 1,1,2-trichloroethene ; 1,1,2,2-tetrachloroethane

B) 1,1,1-trichloroethane & 1,1,1,1-tetrachloroethane

C) Tetrachloroethene & Trichloroethane

D) NOTA

10. Which of the following dipole moment order is correct ?

A) CH3Cl>CH3F>CH3Br> CH3I

B) CH3Cl>CH2Cl2>CHCl3>CCl4

C) O-dichlorobenzene(ODCB) > MDCB > PDCB

D) All of the Above

11. Which of the following statement is incorrect ?

A) RCOOAg + Br2 => RBr + CO2 + AgBr

B) Rxn A is Called Borodine-Hunsdieckar rxn

C) Rxn A operates via Free radical Mechanism

D) Rxn A Reduces one carbon atom Number

E) Yield of RBr decreases as t>s>p

12. CH₃-CH=CH₂ reacts with I) NBS & II) HCl-H2O2 gives respt.

A) Br-CH2-CH=CH2 & CH3-CH2-CH2Cl

B) Br-CH2-CH=CH2 & CH3-CHCl-CH3

C) CH3-CHBr-CH3 & CH3-CHCl-CH3

D) NOTA

13. CH₃-CH₂-CH₂Cl reacts with I) Alc.KOH or NaNH₂ II) Aq. KOH form ….& … respectively

A)ROH & alkene

B) RX & Alcohol

C) alkene & ROH

D) All are possible

14. RX reacts with I) AgNO₂ & II) NaNO₂ form --&---

A) RNO2 & RONO

B) RNO2 only

C) RONO Only

D) RONO & RNO2

15. Which of the following is incorrect reaction?

A)2 RX + 2Na /dryether => RR + 2NaX

B) 4EtCl + 4Na/Pb =>(Et)4Pb + 4NaCl + 3Pb

C) RX + Mg/dryether => RMgX

D) 2EtBr + Zn => Butane + ZnBr2

16. What is major Hoffmann product of reaction

CH3-CH(Br) CH2-CH3 + EtOH-KOH=>

A) CH3CH(OH)CH2-CH3

B) CH3CH2-CH2-CH3

C) CH2=CH-CH2-CH3

D) CH3-CH=CH-CH3

17. Which of the following compound do not give Haloform test Positive

A) CH3-CO-COOH

B) CH3-CH2-OH

C) CH3-CO-CHO

D) CH3-CO-OH

18. A yellow Product is formed when an organic compound C3H8O is warmed with aq. Na2CO3 & I2 solution. The product is

A) CHI3

B) NaI

C) NaIO3

D) Adduct of NaI & C3H8O

19.Identify Z in the following series

EtI + Alc. KOH=>X ; X + Br2=>Y ; Y + KCN=> Z

A) EtCN

B) EtNC

C) NC-CH2-CH2-CN

D) NOTA

20. The Order of SN2 reaction in RX is

A) RF>RCl>RBr>RI

B) RI>RBr>RCl>RF

C) RCl>RF>RBr>RI

D) RF>RBr.>RCl>RI

21. Which of the following is correctly matched or related :-

A) COCl2- Phosgene gas

B) Cl3C-CHO - Chloral

C) Gammexane- 666 or BHC

D) DDT- C₁₄H₉Cl₅

E) Pyrene- CCl4

F) All of the Above

Print Here

Friday 15 July 2022

NEET UG CHEMISTRY WEIGHTAGE

Best of Luck for Your Upcoming Exam .

Here is chapter wise weightage for NEET UG chemistry.

Thursday 14 April 2022

Invest in Our Planet

Invest In our Planet Earth

AJIT SINGH - CHEMISTRY EDUCATOR , TEACHER

It is horrifying that we have to fight with our own trash/waste to protect the environment & the green planet –The Earth. For the first time in 3.8 billion years that life has existed on Earth, one species-humanity has altered the physical, biological & chemical features of the Green planet. Humans blame one & another for its alteration but no one steps up to clear the environmental issues. Neither the policies of Government nor the citizens. Presently, the status of earth is such that people want to settle on another planet. The variety & variability of life on the earth is on extinction due to drastic climatic changes. There is an immediate need to support earth and protect the environment, for this aim to fulfill Earth Day is celebrated annually on 22^nd of April since 1970. This year 2022 –we are celebrating 52^nd anniversary of world Earth Day with Theme 2022- Invest in Our planet.

In 1969 at UNESCO conference in San Francisco , Peace activities John MCconnell proposed a day to honor the Earth and the concept of peace , to be observed on March 21, 1970, the longest day of Northern hemisphere . A month later, US Senator Gaylord Nelson proposed the idea to hold a nationwide environment teach-In on April 22, 1970. He hired a young activist, Denis Hayes to be the national coordinator. Nelson & Hayes re-named the event “Earth Day”. All this was after one of the incident –The famous 1969 Santa Barbara oil Spill, California – a well drilled by Union Oil Platform A off the coast of Santa Barbara, blew out. More than 3 million gallons of oil spewed, killing nearly about 10,000 species below sea. In reaction to this Oil Spill, protests held for regulation of environment laws or policies, Earth day. Today, Earth day is widely recognized by more than a billion people & more than 199 countries.

A similar case witnessed in Bhopal , India popularly known as Bhopal gas Tragedy- 1984 wherein the leakage of poisonous gas (methyl Isocynate) results in death of atleast 4000 people & thousands suffering from disease or medical conditions.

Due to climatic changes – Parkland Vegetation in tropical grassland are on extinction. Everyday there is drastic diminishing of water resources, burning forests, extinction of wildlife etc. All this is because of one species- that is species of Human- with brains of self interest and no use for protection of environmental degradation.

Steps to recover & regenerate a earth includes various plans, acts, conventions /protocol from time to time and their results are slow and agenda will be covered after long run but if humans contribute then they are not so far and the dream of clean & clear environment will be soon achieved.

Theme 2022 _Invest in Our planet is contribution of each & every individual, society, district, state & country to invest in number of ways and reduce the waste burden from earth. Now, you are thinking it is monetary only , No it can be non-monetary also. Here is the ways of contribution for an individual to invest in our planet :-

1) Take first step towards ending plastic pollution – If you use reusable textile bag it can reduce pollution created by 600 polythene bags in just one month. Tell the administration to ban single use plastic

2) Support organic ingredients

3) Encourage use of reusable utensils, dishes & trays

4) Use solar energy, switch off laptop/Tv/Fan & other electronic gadgets when not in use.

5) Save & grow trees – stand against deforestation

6) Organize a community cleanup

7) Pick up trash while you run & walk

8) Compost

9) Go pesticide free –use bio-organic pesticide

10) Eat less meat & Join awareness programs.