Chemistry 1 Marks Question

2, 2, 4-Trimethyl pentan-3-ol.

The nitro-group is an electron-withdrawing group. The presence of this group in the ortho position decreases the electron density in the O-H bond. As a result, it is easier to lose a proton. Also, the o-nitrophenoxide ion formed after the loss of protons is stabilized by resonance. Hence, ortho nitrophenol is a stronger acid. On the other hand, methoxy group is an electron-releasing group. Thus, it increases the electron density in the O-H bond and hence, the proton cannot be given out easily. For this reason, ortho-nitrophenol is more acidic than ortho-methoxyphenol.

When phenol is treated with bromine water, 2,4,6-tribromophenol is formed as white precipitate.

3-Bromocyclohexanol.

Propane-1,2,3-triol.

5-Ethyl heptanes-2, 4-diol.

Ethanol undergoes intermolecular H-bonding due to the presence of a hydrogen atom attached to the electronegative oxygen atom. As a result, ethanol exists as associated molecules.
Consequently, a large amount of energy is required to break these hydrogen bonds. Therefore, the boiling point of ethanol is higher than that of methoxymethane which does not form H-bonds.

1-Methoxypropane.

4-Nitroanisole.

Thus, The Grignard reagent used is

2, 5-Dimethylhexane-1, 3-diol.

Tertiary alcohols > Secondary alcohols > Primary alcohols.

When chloromethylcyclohexane is treated with sodium hydroxide, cyclohexylmethanol is obtained.

When ethyl magnesium chloride is treated with methanal, an adduct is the produced which gives propan-1-ol on hydrolysis.

100% ethyl alcohol is called absolute alcohol.

1. 3-Ethyl-5-methylhexan-2,4-diol.
2. 1-Methoxy-3-3nitrocyclohexan.

3-Chloromethyl-2-isopropylpentan-1-ol.

2-Chlorlo-l-methoxyethane.

If benzyl chloride is treated with NaOH (followed by acidification) then benzyl alcohol is produced.

Due to electron withdrawing effect of phenyl group, the C-O bond in phenol is less polar, whereas in case of methanol the methyl group has electron releasing effect and hence C-O bond in it is more polar. Dipole moment depends upon the polarity of bonds.

Intramolecular H-bonding is present in o-nitrophenol. O-Nitrophenol is steam volatile because of weak intra molecular H-Bonding. In p-nitrophenol, the molecules are strongly associated due to the presence of intermolecular bonding. Hence, o-nitrophenol is steam volatile whereas p-nitrophenol is not.

Propanol has higher boiling point than butane because of wide spread H-bonding among propanol molecules. A lot of energy is required to break inter molecular H-bonding among propanol molecules. There is no such bonding in butane.

Ethyl bromide and sodium tert-butoxide.

The starting material used in the industrial preparation of phenol is cumene.

By acid-catalyzed hydration of ethylbenzene (styrene), 1-phenylethanol can be synthesized.

Strong oxidizing agents such as acidified potassium permanganate are used for getting carboxylic acids from alcohols directly.

1 -Methoxy-2-methyl propane.

Kolbe's reaction:When phenol is treated with sodium hydroxide, sodium phenoxide is produced. This sodium phenoxide when treated with carbon dioxide, followed by acidification, undergoes electrophilic substitution to give ortho-hydroxybenzoic acid as the main product. This reaction is known as Kolbe's reaction.

Since diethyl ether does not contain an active hydrogen attached to oxygen like alcohols and phenols, it does not react with sodium.

Benzene diazonium chloride when heated with water, phenol is formed.

Butane-2, 3-diol.

O=C=O molecule is linear so that the polarities of two C – O bonds get cancelled and the molecule is linear.
Ethers have structures similar to water and have angular or bent structure. Therefore, the polarity of two R – O groups does not get cancelled and these have net dipole moment. Thus, R – O – R is polar.

Ethers are insoluble in water because due to the bigger size of the alkyl groups, the oxygen atom in ethers fails to form intermolecular H-bonds with water.

The -OH group attached to the benzene ring activates it towards electrophilic substitution reaction. Also, it directs the incoming group to ortho and para positions in the ring as these positions become electron rich due to the resonance effect caused by -OH group. That is why nucleophilic substitution reaction is not common in phenol.

Anisole undergoes bromination with bromine in the ethanoic acid even in the absence of iron(lll)bromide catalyst. Due to the activation of benzene ring by the methoxy group. Para isomers is obtained in 90% yield.

Phenol will be easily nitrated since the -OH group attached to the benzene ring activates it towards electrophilic substitution. Also, it directs the incoming group to ortho and para positions in the ring as these positions become electron rich due to the resonance effect caused by -OH group.

Alcohols can form H- bonds with due to presence of (-OH) group and break the H-bonds already existing between water molecules. Hence they are soluble in water.

In contrast, hydrocarbon cannot form H-bonds with water and hence are insoluble in water.

Acidifled or alkaline potassium permanganate.

1-Methoxy-2-methylpropane.

Chlorobenzene is heated with 6 to 8% solution of NaOH to about 623 K under a pressure of 300 atmospheres to form sodium phenate which upon acidification with dilute HCl gives phenol as follows:

1-Phenoxy heptane.

Alkylation of anisole:

Alcohol is made unfit for drinking by mixing some copper sulphate and pyridine to it. This process is called denaturation of alcohol and alcohol mixed with copper sulphate and pyridine is called denatured alcohol.

Ethoxybenzene.

2-Ethoxy butane.

2, 5-Dimethyl phenol.

Rectified spirit containing 95% ethyl alcohol and 5% water forms an azeotropic mixture which distils at a constant temperature of 351.13K.

Due to intramolecular H-bonding o-nitrophenol exists as a discrete molecule whereas due to intermolecular H-bonding p-nitrophenol exists as associated molecules. As a result of this p-nitrophenol has higher boiling point than o-nitrophenol.

Acidified potassium dichromate or neutral/ acidic/ alkaline potassium permanganate.

When methyl magnesium bromide is treated with propane, an adduct is the product which gives 2-methylpropane-2-ol on hydrolysis.

1-Ethoxy-2-methylpropane.

Solubility of alcohols and phenols in water is due to their ability to form hydrogen bonds with water molecules as shown. The solubility decreases with increase in size of alkyl/aryl (hydrophobic groups).