Define ambident nucleophile with an example.

The nucleophiles that can attack through two different sites are known as ambident nucleophiles . For ex :- CN - , NO 2 - , - O - CH = S A cyanide ion can attack through either C atom or N atom to form alkyl cyanide or alkyl isocyanide.

Identify the chiral molecule in the following pair:

For a molecule to be chiral it must have a non-superimposable mirror image. For this, an asymmetric carbon atom (an atom attached to four different atoms or group of atoms) must be present in the molecule. The '*' carbon is asymmetric, therefore, molecule (i) is a chiral molecule.

Predict the major product formed when 2-Bromopentane reacts with alcoholic KOH .

When 2-Bromopentane is treated with an alcoholic KOH nucleophilic substitution reaction takes place and pent-2-ene, pent-1-ene are formed. Pent-2-ene is major product also known as Saytzeff's product, and it is more stable alkene. This reaction involves elimination of β -hydrogen and hence this reaction is called β -elimination reaction.

Give one use of CHI 3 .

CHI 3 is prepared industrially by the electrolysis of an aqueous solution of ethanol or acetone containing sodium carbonate and potassium iodide. It is used as an antiseptic. Its antiseptic properties are due to the liberation of free iodine.

Name the instrument used for measuring the angle by which the plane polarised light is rotated.

Polarimeter is the instrument used for measuring the angle by which the plane polarised light is rotated. Polarimeter consists of a source of monochromatic light, two Nicol prisms and a tube. One Nicol prism is called polariser and the other is called analyser.

Account for the following : t-Butyl chloride on heating with sodium methoxide gives 2-methylpropene instead of t-butylmethylether.

Tertiary alkyl halides on heating with sodium methoxide undergo elimination reaction to yield an alkene as major product. Since, t-butyl chloride is a tertiary halide, the nucleophilic substitution reaction is not possible at the crowded centre. Hence, t-butyl chloride on heating with sodium methoxide gives 2-methylpropene instead of t-butylmethylether.

Write the structure of the alkene formed by dehydrohalogenation of 1 - bromo - 1 - methylcyclohexane with alcoholic KOH .

Dehydrohalogenation of a haloalkane results in the production of an alkene. In general, secondary and tertiary haloalkanes undergo dehydrohalogenation reactions using a strong base in a polar solvent (such as ethanol, EtOH ) at higher temperature (usually heated under reflux). The dehydrohalogenation of 1 - bromo - 1 - methylcyclohexane with alcoholic KOH produces 1 - methylcyclohexene. .

Write the structure of the product when chlorobenzene is treated with methyl chloride in the presence of sodium metal and dry ether.

The chemical reaction of aryl halides with alkyl halides and sodium metal with dry ether present to yield substituted aromatic compounds is called the Wurtz-Fittig reaction. An example of such a reaction is given as, when chlorobenzene is treated with methyl chloride in the presence of sodium metal and dry ether, it can produce the alkyl substituted benzene. .

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter -1 - Haloalkanes and Haloarenes>CBSE-2020>Q 9

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Predict the stereochemistry of the product formed if an optically active alkyl halide undergoes substitution reaction by $S_{N} 1$ mechanism.

Chapter-Wise 3D Chemistry Videos from Embibe Experts EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY

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Polyhalogen Compounds - I

There are several polyhalogen compounds such as dichloromethane, carbon tetrachloride and DDT that have industrial applications. Let’s study their properties!

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Nucleophilic Substitution Reactions

This video explains that the haloarenes and substituted haloarenes undergo nucleophilic substitution reaction. Find out more about this reaction in this video.

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Nucleophilic Substitution Reactions of Haloarenes

This video explains that haloarenes do not undergo nucleophilic substitution reactions under normal conditions and the various reasons for this non-reactivity.