Hydrocarbons (Alkane, Alkene and Alkyne) MCQ Questions & Answers in Organic Chemistry | Chemistry
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171.
Which of the following alkynes is most acidic?
A
$$C{H_3}C \equiv CH$$
B
$$C{H_3}C \equiv CC{H_3}$$
C
$$C{H_3}C{H_2}C \equiv CH$$
D
$$CH \equiv CH$$
Answer :
$$CH \equiv CH$$
$$+I$$ effect of $$-R$$ group decreases acidity of acetylinic $$H$$ - atom.
172.
The major product formed in the reaction is : \[\xrightarrow[\text{(mononitration)}]{Conc.\,HN{{O}_{3}}/conc.\,{{H}_{2}}S{{O}_{4}}}\]
A
B
C
D
Answer :
because of steric factor para is major.
173.
Observe the following reactions and predict the products $$A$$ and $$B.$$
A
B
C
D
Answer :
174.
In which step of the following reaction, $$s{p^3}$$ carbon changes to $$s{p^2}$$ carbon ?
A
Step 1
B
Step 2
C
Both
D
None
Answer :
Step 2
Step 1 involves the conversion of $$s{p^2}$$ carbon to $$s{p^3}$$ carbon ( carbon having electrophile $$E$$ ) while step 2 involves the conversion of $$s{p^3}$$ carbon to $$s{p^2}$$ carbon.
175.
The gas liberated by the electrolysis of dipotassium succinate solution is :
A
Ethane
B
Ethyne
C
Ethene
D
Propene
Answer :
Ethene
Ethene is obtained by electrolysis of dipotassium succinate as follows
At anode :
At cathode :
$$2{H^ + } + 2{e^ - } \to \left[ {2H} \right] \to {H_2}$$
176.
When 3,3-dimethyl-2-butanol is heated with $$conc.\,{H_2}S{O_4},$$ the major product obtained is
A
2, 3-dimethyl-2-butene
B
3, 3-dimethyl-2-butene
C
2, 3-dimethyl-1-butene
D
$$cis$$ and $$trans$$ -isomers of 2, 3-dimethyl-2- butene
Answer :
2, 3-dimethyl-2-butene
177.
Which of the following products is formed when $$n$$ - heptane is passed over $$\left( {A{l_2}{O_3} + C{r_2}{O_3}} \right)$$ catalyst at $$773\,K?$$