Bihar Board 12th Chemistry VVI Objective Questions Model Set 1 in English

Bihar Board 12th Chemistry Objective Questions and Answers

Bihar Board 12th Chemistry VVI Objective Questions Model Set 1 in English

Question 1.
A dilute aqueous solution of sodium fluoride is electrolysed; the products at the anode and cathode are
(a) F₂, Na
(b) F₂, H₂
(c) O₂, Na
(d) O₂, H₂
Answer:
(b) F₂, H₂

Question 2.
Number of σ and π bonds in C₂ molecule is/are
(a) 1σ and 1π
(b) 1σ and 2π
(c) 2π only
(d) 1σ and 3π
Answer:
(b) 1σ and 2π

Question 3.
Rate of hydration in aqueous acid will be in the order

(a) I < II < III
(b) III < II < I
(c) I < III < II
(d) II < I < III
Answer:
(d) II < I < III

Question 4.
The molecule which has zero dipole moment is
(a) NF₃
(b) BF₃
(c) ClO₂
(d) CH₂Cl₂
Answer:
(b) BF₃

Question 5.
The correct order of equivalent conductance at infinite dilution of LiCl, NaCl and KCl is
(a) LiCl > NaCl > KCl
(b) KCl > NaCl > LiCl
(c) NaCl > KCl > LiCl
(d) LiCl > KCl > NaCl
Answer:
(b) KCl > NaCl > LiCl

Question 6.
R-OH + CH₂N₂ → Leaving group in this reaction is
(a) CH₃
(b) R
(C) N₂
(d) CH₂
Answer:
(a) CH₃

Question 7.
The product obtained when silica reacts with hydrogen fluoride is
(a) SiF₄
(b) H₂SiF₆
(c) H₂SiF₄
(d) H₂SiF₃
Answer:
(b) H2SiF6

Question 8.
The van’t Hoffs factor of 0.1 M Ba(NO₂)₂ solution is 2.74. The degree of dissociation is
(a) 91.3%
(b) 87%
(c) 100%
(d) 74%
Answer:
(b) 87%

Question 9.
Which of the following has the most stable +2 oxidation state?
(a) Sn
(b) Ag
(c) Fe
(d) Pb
Answer:
(d) Pb

Question 10.
The compound having tetrahedral geometry is
(a) [NiCl₄]^2-
(b) [Ni(CN)₄]^2-
(c) [PdCl₄]^2-
(d) [NiCl₄]^2- and [PdCl₄]^2-
Answer:
(a) [NiCl₄]^2-

Question 11.
The Cannizzaro’s reaction is not given by
(a) Formaldehyde
(b) Acetaldehyde
(c) Benzaldehyde
(d) Furfural
Answer:
(b) Acetaldehyde

Question 12.
Which represents a zero-order reaction?

Answer:

Question 13.
Which gas is absorbed strongly by charcoal?
(a) CO
(b) NH₃
(C) NCl₃
(d) H₂
Answer:
(a) CO

Question 14.
If \(\frac{d x}{d t}\) = K[H+]ⁿ and rate becomes 100 times when pH changes from 2 to 1, the order of reaction is
(a) 1
(b) 2
(c) 3
(d) 0
Answer:
(c) 3

Question 15.
Equivalent conductance of saturated BaSO₄ is 400 ohm^-1 cm² eqvt^-1 and specific conductance is 8 × 10^-5 ohm^-1. The K_sp of BaSO₄ is
(a) 4 × 10^-8 M²
(b) 10^-8 M²
(c) 2 × 10^-4 M²
(d) 10^-4 M²
Answer:
(c) 2 × 10^-4 M²

Question 16.
An organic compound gives the iodoform test and also gives a positive test with Tollens reagent. The compound is

Answer:
(c) CH₃ – CH₂OH

Question 17.
IUPAC name of H₂[Pt Cl₆] is
(a) Hydrogen hexachloro platinate (IV)
(b) Hydrogen hexachloro platinate (II)
(c) Hydgoren Hexa chloride Pt (IV)
(d) Hydrogen Hexa chloride Pt (II)
Answer:
(d) Hydrogen Hexa chloride Pt (II)

Question 18.
Mercuric chloride reacts with ammonia gas and forms a white precipitate. The molecular formula of the white precipitate is
(a) HgCl₂. 2NH₃
(b) Hg(NH₃)₂ Cl₂
(c) Hg(NH₂) Cl₂
(d) Hg(NH₂) Cl
Answer:
(a) HgCl₂. 2NH₃

Question 19.
Which alkyl halide follows only SN² hydrolysis mechanism?
(a) CH₃ – CH₂ – X

(c) (CH₃)₃ C – X
(d) C₆H₅ – CH₂X
Answer:
(c) (CH₃)₃ C – X

Question 20.

Half-life of this reaction is independent of concentration of reactant. After 10 minutes volume of N₂ gas is 10 litre and after complete reaction 100 litre. The rate constant of the reaction in min^-1 unit is
(a) \(\frac{2.303}{10}\)
(b) \(\frac{2.303}{10}\) log 5.0
(c) \(\frac{2.303}{10}\) log 2.0
(d) \(\frac{2.303}{10}\) log 4.0
Answer:
(b) \(\frac{2.303}{10}\) log 5.0

Question 21.
When NaCl solution is added to Fe(OH)₃ colloidal solution then
(a) [Fe(OH₃)] Fe³⁺ is formed
(b) [Fe(OH₃)] Cl^– is formed
(c) [Fe(OH₃)] Na⁺ is formed
(d) Fe(OH)₃ is formed
Answer:
(a) [Fe(OH₃)] Fe³⁺ is formed

Question 22.
Which complex has a maximum paramagnetic moment value amongst the following
(a) [Cr(H₂O)₆]³⁺
(b) [Fe(H₂O)₆]Cl₂
(c) [Fe(CN)₆]^4-
(d) [Ni(CO)₄]
Answer:
(d) [Ni(CO)₄]

Question 23.
Which of the following gives a yellow or brown precipitate with alkaline Nessler’s reagent?
(a) CO₂
(b) NH₃
(c) NaCl
(d) KI
Answer:
(b) NH₃

Question 24.
A 5% solution of cane sugar (Mol. Wt = 342) is isotonic with 1 % solution of substance X. The molecular weight of X is
(a) 68.4
(b) 34.2
(c) 171.2
(d) 136.2
Answer:
(b) 34.2

Question 25.

(a) 1.36 V
(b) 1.30 V
(c) 1.42 V
(d) 1.20 V
Answer:
(c) 1.42 V

Question 26.
An Organic compound reacts with benzene sulfonyl chloride and product dissolves in aqueous NaOH. The compound is
(a) R – NH₂


(d) all of these
Answer:
(a) R – NH₂

Question 27.
A compound on hydrolysis gives 1°- amine. The compound is
(a) anilide
(b) amide
(c) cyanide
(d) None
Answer:
(c) cyanide

Question 28.

This reaction is known as
(a) Stephen’s reaction
(b) Cannizzaro’s reaction
(c) Rosenmund’s reaction
(d) Hinsberg’s reaction
Answer:
(c) Rosenmund’s reaction

Question 29.
Percentage of free space in bcc. unit cell is
(a) 32%
(b) 34%
(c) 28%
(d) 30%
Answer:
(a) 32%

Question 30.
The coordination number of a metal crystallizing in hexagonal close-packed (hcp) structure is
(a) 12
(b) 8
(c) 4
(d) 6
Answer:
(a) 12

Question 31.
Which of the following compound is most reactive towards nucleophilic addition?

Answer:

Question 32.
Copper sulphate solution on treatment with an excess of KI gives whitish precipitate. The precipitate
(a) CuI₂
(b) Cu₂I₂
(c) Cu₂SO₄
(d) I₂
Answer:
(b) Cu₂I₂

Question 33.
The most stable oxidation state of bismuth is
(a) +3
(b) +5
(c) +3 and +5 both
(d) None
Answer:
(a) +3

Question 34.
Which metal nitrate gives colourless gas on thermal decomposition?
(a) NaNO₃
(b) Cu(NO₃)₂
(c) Ba(NO₃)₂
(d) Hg(NO₃)₂
Answer:
(c) Ba(NO₃)₂

Question 35.
In which of the following pairs of structures are tetrahedral as well as octahedral voids respectively?
(a) bcc and fcc
(b) hcp and simple cubic
(c) hcp and ccp
(d) bcc and hcp
Answer:
(d) bcc and hcp