Bihar Board 12th Chemistry Objective Important Questions Part 5 in English

BSEB Bihar Board 12th Chemistry Important Questions Objective Type Part 5 are the best resource for students which helps in revision.

Bihar Board 12th Chemistry Objective Important Questions Part 5 in English

Question 1.
Chloral is:
(a) CCl₃CHO
(b) CCl₃CH₃
(c) CCl₃COCH₃
(d) CCl₃CH₂OH
Answer:
(a) CCl₃CHO

Question 2.
Amongst the following the most reactive alkyl halide is :
(a) C₂H₅Br
(b) C₂H₅I
(c) C₂H₅Cl
(d) All are same
Answer:
(a) C₂H₅Br

Question 3.
Amongst the following which one is the most reactive?
(a) CH₃CH₂I
(b) C₂H₅Br
(c) (CH₃)₃Cl
(d) All are same
Answer:
(c) (CH₃)₃Cl

Question 4.
Ethyl iodide on treatment with moist silver oxide gives :
(a) acetic acid
(b) ethyl alcohol
(c) acetaldehyde
(d)none
Answer:
(b) ethyl alcohol

Question 5.
Amongst the following, the one having the highest boiling point is :
(a) C₂H₅Cl
(b) C₂H₅Br
(c) C₂H₅I
(d) CH₃Cl
Answer:
(c) C₂H₅I

Question 6.
Which one of the following will give ethyl alcohol when heated with moist silver oxide:
(a) CH₃I
(b) C₂H₅Br
(c) (CH₃)₂CHI
(d) CH₃-CH₂-CH₂I
Answer:
(b) C₂H₅Br

Question 7.
Amongst the following which one has the highest boiling point?
(a) ethyl alcohol
(b) n-propyl alcohol
(c) n-butyl alcohol
(d) methyl alcohol
Answer:
(c) n-butyl alcohol

Question 8.
Which one is the most acidic?
(a) CH₃OH
(b) C₂H₅OH
(c) CH₃·CH(OH)·CH₃
(d) CH₃·CH₂·CH₂OH
Answer:
(a) CH₃OH

Question 9.
Ethyl alcohol, when oxidised with acidic K₂Cr₂O₇ solution, gives:
(a) CH₃·COOH
(b) HCOOH
(c) CH₃·CO·CH₃
(d) None
Answer:
(a) CH₃·COOH

Question 10.
Which one of the following will give an aldehyde on oxidation with chromic anhydride in glacial acetic acid?
(a) CH₂COOH
(b) CH₃CH(OH)CH₃
(c) CH₃ CH₂OH
(d) None
Answer:
(c) CH₃ CH₂OH

Question 11.
Which one of the following will give a ketone on oxidation with acidic K₂Cr₂O₇ ?
(a) CH₃ CH₂OH
(b) CH₃CH (OH)CH₃
(c) CH₃OH
(d) None
Answer:
(b) CH₃CH (OH)CH₃

Question 12.
Which one of the following reduces Fehling’s solution?
(a) CH₃COOH
(b) CH₃COCH₃
(c) HCHO
(d) CH₃OH
Answer:
(c) HCHO

Question 13.
Which one of the following undergoes Cannizzaro reaction?
(a) HCHO
(b) CH₃ CHO
(c) CH₃COCH₃

Answer:
(a) HCHO

Question 14.
Dry distillation of calcium acetate will give :
(a) CH₃ COOH
(b) CH₃COCH₃
(c) CH₃ CHO
(d) CH₃ · CH₃
Answer:
(b) CH₃COCH₃

Question 15.
Which will turn blue litmus red?
(a) HCOOH
(b) CH₃CHO
(C) CH₃COCH₃
(d) None
Answer:
(a) HCOOH

Question 16.
When a mixture of calcium acetate and calcium formate is heated. it yields:
(a) acetone
(b) formic acid
(e) acetic acid
(d) acetaldehyde
Answer:
(d) acetaldehyde

Question 17.
Carboxylic acids do not give the characteristic properties of:
(a) >C = O group
(b) -COOH group
(c) Alkyl group
(d) none of these
Answer:
(a) >C = O group

Question 18.
Which one is a phenol?
(a) C₆H₅CH₂OH
(b) C₆H₅OH
(c) CH₃CH₂OH
(d) None
Answer:
(b) C₆H₅OH

Question 19.
Which is the strongest acid
(a) p-phenol
(b) m-phenol
(c) o-phenol
(d) phenol
Answer:
(a) p-phenol

Question 20.
Which of the following turns litmus red?
(a) CH₃CH₂OH
(b) C₆H₅CHO
(c) C₆H₅OH
(d) None
Answer:
(c) C₆H₅OH

Question 21.
Phenols do not react with :
(a) NaOH
(b) KOH
(c) NaHCO₃
(d) None
Answer:
(c) NaHCO₃

Question 22.
Amongst the following the most acidic oxide is:
(a) Sb₂O₅
(b) P₂O₅
(c) N₂O₅
(d) AS₂O₅
Answer:
(c) N₂O₅

Question 23.
The cause of variable valency-among transition dementias:
(a) They all exist in more than one oxidation state
(b) They all form complex compounds
(c) the valence electrons of them are found in two different subshells
(d) they all have paired electrons
Answer:
(c) the valence electrons of them are found in two different subshells

Question 24.
Which one is not a transition element?
(a) Co
(b) V
(c) Ge
(d) Rh
Answer:
(c) Ge

Question 25.
Froth floatation process is used :
(a) for calcination of ores
(b) for roasting of ores
(c) for concentration of ores
(d) for smelting of ores
Answer:
(c) for concentration of ores

Question 26.
Sulphide ores are concentrated by :
(a) gravity separation
(b) electromagnetic separation
(c) froth floatation process
(d) None of these
Answer:
(c) froth floatation process

Question 27.
Froth floatation process is used for the concentration of:
(a) sulphide ores
(b) carbonate ores
(c) oxide ores
(d) sulphate ores
Answer:
(a) sulphide ores

Question 28.
Which of the following ores is concentrated by froth floatation process:
(a) Bauxite
(b) cassiterite
(c) galena
(d) siderite
Answer:
(c) galena

Question 29.
When one Faraday of Electric current is passed. The Mass deposited is equal to :
(a) One gram equivalent
(b) One gram Mole
(c) Electro-chemical equivalent
(d) Half gram equivalent
Answer:
(a) One gram equivalent

Question 30.
Amongst the following the most acidic oxide is :
(a) N₂O₃
(b) N₂O₅
(c) N₂O₄
(d) All are same
Answer:
(b) N₂O₅

Question 31.
Thermally most stable oxide is :
(a ) P₂O₃
(b) As₂O₃
(c) Sb₂O₃
(d) N₂O₃
Answer:
(d) N₂O₃

Question 32.
Which is the most stable:
(a) N₂O₃
(b) N₂O₅
(c) N₂O₄
(d) All are same
Answer:
(a) N₂O₃

Question 33.
Which one is the most basic?
(a) NH₃
(b) AsH₃
(c) SbH₃
(d) PH₃
Answer:
(a) NH₃

Question 34.
Which one is the most stable?
(a) PH₃
(b) NH₃
(c) SbH₃
(d) AsH₃
Answer:
(b) NH₃

Question 35.
Which is stronger reducing agent?
(a) PH₃
(b) NH₃
(c) SbH₃
(d) AsH₃
Answer:
(c) SbH₃

Question 36.
Which of the folIowingeOmpounds is least acidic?
(a) H₂Se
(b) H₂O
(c) H₂S
(d) H₂Te
Answer:
(b) H₂O

Question 37.
Which of the following compounds is most stable?
(a) H₂O
(b) H₂Te
(c) H₂S
(d) H₂Se
Answer:
(a) H₂O

Question 38.
Which of the following is the strongest reducing agent?
(a) H₂O
(b) H₂Se
(c) H₂Te
(d) H₂S
Answer:
(c) H₂Te

Question 39.
Which of the following aqueous solution should have highest boiling point:
(a) 1.0 M NaOH
(b) 1.0 M Na₂SO₄
(c) 1.0 M NH₄NO₃
(d) 1.0 M KNO₃
Answer:
(b) 1.0 M Na₂SO₄

Question 40.
A solution has an osmotic pressure of 0.0821 atm at 300K. Its concentration would be:
(a) 0.66 M
(b) 0.32 M
(c) 0.066 M
(d) 0.0033 M
Answer:
(d) 0.0033 M

Question 41.
Azeotropic mixture of HCl and H₂O has :
(a) 48% HCl
(b) 22.2% HCl
(c) 36% HCl
(d) 20.2% HCl
Answer:
(d) 20.2% HCl

Question 42.
For a zero order reaction :

Answer:
(a) t_1/2 ∝ a

Question 43.
The rate at which a substance reacts depends upon its:
(a) Atomic mass
(b) Equivalent mass
(c) Molecular mass
(d) Active mass
Answer:
(d) Active mass

Question 44.
Which of the following is Tribasic :
(a) H₃PO₂
(b) H₃PO₃
(c) H₄P₂O₇
(d) H₃PO₄
Answer:
(d) H₃PO₄

Question 45.
Froth floatation process is based on :
(a) specific gravity of ore particles
(b) magnetic properties of the ore particles
(c) electrical properties of the ore particles
(d) wetting properties of the ore particles
Answer:
(d) wetting properties of the ore particles

Question 46.
The most common oxidation state shown by first row transition elements is:
(a) + 2
(b) + 3
(c) + 4
(d) All of these
Answer:
(a) + 2