General Organic Chemistry MCQ Questions & Answers in Organic Chemistry | Chemistry
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211.
Inductive effect involves
A
displacement of $$\sigma $$ - electrons resulting in polarisation
B
displacement of $$\pi $$ - electrons resulting in polarisation
C
delocalisation of $$\sigma $$ - electrons
D
delocalisation of $$\pi $$ - electrons
Answer :
displacement of $$\sigma $$ - electrons resulting in polarisation
No explanation is given for this question. Let's discuss the answer together.
212.
The chirality of the compound is
A
$$R$$
B
$$S$$
C
$$Z$$
D
$$E$$
Answer :
$$R$$
213.
If on adding $$FeC{l_3}$$ solution to acidified Lassaigne solution, a blood red colouration is produced, it indicates the presence of
214.
During hearing of a court case, the judge suspected that some changes in the documents had been carried out. He asked the forensic department to check the ink used at two different places. According to you which technique can give the best results?
A
Column chromatography
B
Solvent extraction
C
Distillation
D
Thin layer chromatography
Answer :
Thin layer chromatography
Thin layer chromatography method can give the best results as it can be used to separate the components present in a small amount of the sample.
215.
Which of the following compounds is not chiral ?
A
1- chloro - 2 - methyl pentane
B
2 - chloropentane
C
1 - chloropentane
D
3 - chloro - 2 - methyl pentane
Answer :
1 - chloropentane
1 - chloropentane is not chiral while others are chiral in
nature
216.
Which of the following is the strongest base ?
A
B
C
D
Answer :
Lone pair of electrons present on the nitrogen of benzyl amine is not involved in resonance.
217.
Hyperconjugation is not possible in
A
B
C
D
Answer :
No explanation is given for this question. Let's discuss the answer together.
218.
Which of the following reactions is an example of nucleophilic substitution reaction?
A
$$RX + KOH \to ROH + KX$$
B
$$2\,RX + 2\,Na \to R - R + 2NaX$$
C
$$RX + {H_2} \to RH + HX$$
D
$$RX + Mg \to RMgX$$
Answer :
$$RX + KOH \to ROH + KX$$
$$\eqalign{
& KOH \to {K^ + } + O{H^ - } \cr
& RX + \mathop {O{H^ - }}\limits_{{\text{Nucleophile}}} \to R - OH + {X^ - } \cr} $$
$$O{H^ - }$$ is a stronger nucleophile than halogen. So it easily replace the weaker nucleophile.
Nucleophiles are either negative charge or lone pair of electrons bearing species, e.g. $$O{H^ - },\ddot N{H_3},\,$$ etc.
219.
Base strength of
$$\eqalign{
& \left( {\text{i}} \right)\,{H_3}C\mathop C\limits^\Theta \,{H_2} \cr
& \left( {{\text{ii}}} \right)\,{H_2}C = \mathop C\limits^\Theta H \cr
& \left( {{\text{iii}}} \right)H - C \equiv \mathop C\limits^\Theta \cr} $$
is in the order of
A
(ii) > (i) > (iii)
B
(iii) > (ii) > (i)
C
(i) > (iii) > (ii)
D
(i) > (ii) > (iii)
Answer :
(i) > (ii) > (iii)
Weaker the acid, stronger is its conjugate base. Among alkane, alkene and alkyne, alkynes are most acidic and alkanes are least acidic, so the order of base strength is
$$\eqalign{
& alkane > alkene > \,alkyne\,\,\,\,\,\,{\text{or}} \cr
& C{H_3}\mathop C\limits^\Theta {H_2} > {H_2}C = \mathop C\limits^\Theta H > H - C \equiv \mathop C\limits^\Theta \cr} $$
220.
How many degrees of unsaturation are there in the following compound ?