Test: Chemistry- 12

QUESTION: 1

An alkylmagnesium halide reacts with water to give an alkane. In this reaction water acts as

A. an acid
B. a base
C. a catalyst
D. a solvent

Solution:

QUESTION: 2

The reactivity of the halogens towards methane decreases in the order

Solution:

QUESTION: 3

Which of the following statements is correct in relation to the halogenation of alkanes ?

A. Chorine atom is regioselective in abstracting hydrogen in preference to and hydrogens while bromine atom preferm to abstract hydrogens
B. Both chlorine and bromine atoms prefer to abstract hydrogen but chlorine is much more selective than bromine.
C. Both chlorine and bromine atoms prefer to abstract hydrogen to the same extent
D. Bromin atom has a much higher regioselectivity than chlorine atom in abstracting hydrogen

Solution:

QUESTION: 4

Which of the following reactions will lead to the creation of two chiral centers in the product ?

Solution:

QUESTION: 5

trans-2-Buten on reaction with

forms

A. ( )-2,3-dibromobutane
B. meso-2,3-dibromobutane
C. an equimolecular mixiture of (1) and (2)
D. 1,4-dibromo-2-butene

Solution:

QUESTION: 6

1-Methylcyclohexene is allowed to react with

The product is then treated with

and NaOH. The reaction is

The product formed is

A. 1-methylcyclohexanol
B. 2-emthylcyclohexanol
C. trans-2-methylcyclohexanol
D. cis-2-methylcyclohexanol

Solution:

QUESTION: 7

By which of the following reactions can the conversion of cychlohexene (I) into 1,3-cyclohexadiene (III) be effected

A.
B.
C. Both 1 and 2
D. None of 1 and 2

Solution:

QUESTION: 8

Which of the following decolorizes the red-brown of a dilute solution of

in water ?

A.
B.
C.
D. All of these

Solution:

QUESTION: 9

From which of the following hydrocarbons may hydrogen be displaced by a strongly electropositive
metal ?

Solution:

QUESTION: 10

When propyne is treated with aqueous

,the major product formed is

A. propanal
B. 2-propanol
C. propanone
D. propyl hydrogen sulphate

Solution:

QUESTION: 11

Consider the following reaction sequence

The products (A) and (B) are, respectively

Solution:

QUESTION: 12

A hydrocarbon (A) is allowed to react with sodium amide and then with ethyl bromide to produce another hydrocarbon (B) which one ozonolysis produces propanoic acid only. The hydrocarbons (A) and (B) are, respectvely,

A. propyne and 2-pentyne
B. 1-butyne and 3-hexyne
C. propyne and 3-hexyne
D. 1-butyen and 3-hexene

Solution:

QUESTION: 13

Acetylene does not react with

A. Na
B. ammoniacal
C. HCl
D. NaOH

Solution:

QUESTION: 14

Which of the following hydrocarbons should be choosen as a starting material to prepare 3-hexanone by the hydration of the former ?

Solution:

QUESTION: 15

Chlorination of toluene in the presence of light and heat followed by treatement with aqueous NaOH and subsequently with dilute HCl gives

A. o-cresol
B. p-cresol
C. 2,4-dihydroxytoluene
D. benzoic acid

Solution:

QUESTION: 16

Among the compounds

the order of decreasing reactivity towards electrophilic substitution is

A. II > I > III > IV
B. III > I > II > IV
C. IV > I > II > III
D. I > II > III > IV

Solution:

QUESTION: 17

The function of anhydrous

in Fridel–Crafts reaction is to

A. absrob water
B. absorb HCl
C. produce a nucleophile
D. produce an electrophile

Solution:

QUESTION: 18

The smallest alkane having a

carbon is

A. isobutane
B. neopentane
C. isohexane
D. ispentane

Solution:

QUESTION: 19

In which of the following reactions is

Solution:

QUESTION: 20

For the equilibrium

If the equilibrium concentration of

and

respectively then the concentration of HCl is

Solution:

QUESTION: 21

In the reaction

the value of the equilibrium constant depends on

A. the volume of the reaction vessel
B. the initial concentrations of and
C. the temperature
D. the pressure of the system

Solution:

QUESTION: 22

Consider the equilibrium,

The equilibrium constant K is given by (when

)

Solution:

QUESTION: 23

1.7 g of

is present in a 2-L flask. The active mass of

A. 0.1 M
B. 0.05 M
C. 0.5 M
D. 0.02 M

Solution:

QUESTION: 24

For the equilibrium

Solution:

QUESTION: 25

For the eqilibrium,

+14.6 kcal increase in temperature would

A. favour the formation of
B. favour the decomposition of
C. not alter the equilibirium
D. stop the reaction

Solution:

QUESTION: 26

When 1 mole of ethanol is mixed with 1 mole of acetic acid, 0.67 mole of ethyl acetate is produced at equilibrium. Calculate

for the reaction

A. 0.25
B. 6.0
C. 4.0
D. 2.0

Solution:

QUESTION: 27

During thermal dissoication, the observed vapour..........

is 26.0. Calculate the extent of
dissociation of

(g)

A. 50%
B. 87%
C. 77%
D. 23%

Solution:

QUESTION: 28

When

is heated in a closed vessel,

gas is liberated and

is left behind

,At equilibrium

A. addition of favours the reverse reaction
B. addition of favours the forward reaction
C. increasing the temperature favour the forward reaction
D. decreasing the pressure favours the reverse reaction

Solution:

QUESTION: 29

For the heterogeneous equilibrium

the value of

Solution:

QUESTION: 30

The pH of a

M HCl solution is

A. 2.6
B. 4.4
C. 2.4
D. 2.7

Solution:

QUESTION: 31

The pH of a solution formed by maixing 40.0 mL of 0.1 M HCl with 10.0 mL of NaOH is

A.
10.0
B.
8.0
C.
6.0
D.
12.0

Solution:

40ml of 0.1MHCl
(0.1/1000)×40
= 0.004 moles of HCl
Similarly, 10ml of 0.45MNaOH
= (0.45)/1000 × 10
= 0.0045 moles of NaOH
Thus, NaOH left unneutralised = 0.0005 moles in a volume of 50ml
Concentration of NaOH = (1000×0.0005)/50=0.01
= 10^-2M
Therefore, [OH^-]=10^-2M or [H+]
= 10^-12M or pH = 12.0