hydrocarbons-quiz-7

Hydrocarbons Quiz-7

Dear Readers,

The one subject in NEET which is candidates who can easily attain good marks is Chemistry. That's the reason, often, one doesn’t pay notice and choose to compromise it. But if one wants to rank above others, the tip is to be thorough with NEET chemistry concepts. The understanding of reactions and definite basic understanding is what requires major attention in Chemistry but once done it only gets simpler from there. The main focus on the to-do list should be on getting a hang of the NCERT syllabus of NEET chemistry..

Q1. Presence of a nitro group in a benzene ring

•  Activates the ring towards electrophilic substitution
•  Renders the ring basic
•  Deactivates the ring towards nucleophilic substitution
•  Deactivates the ring towards electrophilic substitution

Solution
(d) -NO₂ group withdraw electron from the ring shows-M effect makes ring electron deficient, thus deactivates ring for electrophilic substitution.  

Q2.Propyne on passing through red hot iron tube gives

•  
  
  
•  
  
  
•  
  
  
•  None of these

Solution

Q3. When butane-1 is mixed with excess of bromine, the expected reaction product is: 

•  Hydrogen bromide
•  Butylene gas
•  1,2-dibromobutane
•  Perbromobutane

Solution

Q4. Reaction of trans-2-phenyl-1-bromocyclopentane on reaction with alcoholic KOH produces:

•  4-phenylcyclopentene
•  2-phenylcyclopentene
•  1-phenylcyclopentene
•  3-phenylcyclopentene

Solution
(c) 1-phenylcyclopentene

Q5.What volume of methane (NTP) is formed from 8.2 g of sodium acetate by fusion with sodalime?

•  10 litre
•  11.2 litre
•  5.6 litre
•  2.24 litre

Solution
 

 

Q6. When a mixture of methane and oxygen is passed through heated molybdenum oxide, the main product formed is

•  Methanoic acid
•  Ethanal
•  Methanol
•  Methanal

Solution

 

Q7.Two jars A and B are filled with hydrocarbons. Br₂ in CCl₄ is added to these jars. A does not decolourise the Br₂ solution but B decolourises. What are A and B?

•  Alkane and alkene
•  Alkene and alkane
•  Alkene and alkyne
•  None of these

Solution

(a) Br₂ solution is decolourized by alkene or alkyne or molecules having unsaturation.

Q8.Which of the following is unsymmetrical alkene?

•  1-butene
•  2-hexene
•  1-pentene
•  All of these

Solution
(d) e.g., CH₃ CH₂ CH=CH₂ is unsymmetrical. CH₃ CH=CHCH₃ is symmetrical. Note the positions of carbon atoms on two sides of double bond.  

Q9.When HCI gas is passed through propene in the presence of benzoyl peroxide, it gives:

•  n-propyl chloride
•  2-chloropropane
•  Allyl chloride
•  No reaction

Solution

(b) Peroxide effect is noticed only in case of HBr. For HCl follow Markownikoff’s rule.

Q10. The carbon-carbon bond distance in benzene is

•  Longer than a C-C single bond
•  Longer than a C=C double bond
•  Shorter than a C=C double bond
•  Shorter than a C≡C triple bond

Solution

(b) According to X-ray analysis all carbon-carbon bond distance (1.397Å) are equal in benzene. The bond order of carbon-carbon bond is 1.5 in benzene. Hence, carbon-carbon bond distance (1.397Å) is less than C-C single bond (1.54Å) and more than C=C double bond(1.33Å).