Bihar Board 12th Chemistry Objective Important Questions Part 5 in English
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) t1/2 ∝ 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