12th class (fsc) Chemistry unit 9 MCQs
26. Which xylene gives only one monobromo derivatives?
a. Ortho
b. Para
c. Meta
d. None of these
27. Ortho, para directing groups are generally.
a. Deactivating groups
b. Activating groups
c. Neutral groups
d. None of these
28. When toluene react with methyl chloride in presence of anhydrous AICI3 , it forms:
a. M-xylene
b. 1,3,5 Triethyl
c. o-and p-xylene
d. Diphenyl methane
29. Which of the following compounds reacts slower than benzene in electrophilic substitution/
a. -C6H5
b. C6H5-OH
c. C6H5-NH???????
d. C6H5-NH???????
30. Amongest the following strongest o-,p directing group is:
a. -C6H5
b. -CI
c. -Br
d. -OH
31. Aromatization of n-heptane gives:
a. Benzene
b. Cycloheptane
c. Touene
d. Cyclohexane
32. The conversion of n-hexane into benzene by heating in presence of Cr2O3 is called:
a. Dealkylation
b. Rearrangment
c. Isomerization
d. Aromatization
33. A nucleophile must have overall:
a. Negative charge
b. An unpaired electron
c. A lone pair electrons
d. All of above
34. Acylation of benzene to product aliphatic aromatic ketones is known as:
a. Electron deficient
b. Insoluble in chloride and aluminium ion
c. Electron rich
d. Soluble in ether
35. Although benzene contains double bonds, but does not give additions reactions under ordinary conditions because:
a. Double bonds in benzene are strong
b. Resonance lowers the energy of benzene molecule and lead to greater stability
c. Double bonds change their position rapidly
d. All of them
36. Benzene on catalytic oxidation at 500o C with V2 O5 as catalyst gives;
a. Maleic acid
b. Benzonic acid
c. Acetylene
d. Maleic anhydride
37. Which of the following acids can be used as catalyst in Friedal-Craft’s reaction?
a. HNO3
b. ZNCI2
c. AICI3
d. HCL
38. Which of the following is not an alectrophile:
a. ZnCI2
b. BF3
c. NH4
d. AICI3
39. The reaction of toluene with CI2 in presence of FeCI3 gives mainly:
a. Mchlorotoluence
b. Benzoyl chloride
c. 0- and p chlorotoluene
d. Benzyl chloride
40. When phenol is distilled with zinc dust, it is converted into:
a. Alcohol
b. Toluene
c. Benzene
d. Aniline
41. Benzene undergoes substitution reactions more easily than addition reactions because:
a. It has six hydrogen atom
b. It has cyclic structure
c. Delocalization of electrons
d. It has three double bond
42. In the presence of sunlight, benzene reacts with CI2 to give:
a. Pt
b. HCL
c. CI–
d. CI+
43. The catalyst used for the halogenations of benzene is:
a. Pt
b. FeX3
c. Ni
d. AICI3
44. The benzene molecule contains:
a. One double bonds
b. Three double bonds
c. Delocalized it electron charge
d. Two double bonds
45. Aromatic hydrocarbons are the derivatives of:
a. Benzene
b. Normal series of paraffins
c. Cyclohexane
d. Alkene
46. Which of the following acid can be used as catalyst in Friedel-crafts reactions?
a. BeCI2
b. ALCI3
c. NaCI
d. HNO3
47. Benzene cannot undergo:
a. Oxidation reactions
b. Substitution
c. Elimination reactions
d. Addition reactions
48. Amongest the following, the compound that can be most readily sulphonated is:
a. Nitrobenzene
b. Toluene
c. Chlorobenzene
d. Benzene
49. During nitration of benzene, the active nitrating agent is:
a. NO4
b. NO3
c. HNO3
d. NO2
50. Which compound is the most reactive one:
a. Ethane
b. Benzene
c. Ethyne
d. Ethene