Chemistry 2 Marks Questions

Although the addition of sulphuric acid will precipitate lead sulphate, the addition of acetic acid will ensure a complete precipitation of sulphur in the form of lead sulphate due to common ion effect. Hence, it is necessary to use acetic acid for acidification of sodium extract for testing sulphur by lead acetate test.

1. 3-Ethyl-4,7-dimethyl nonane.
2. 1-Ethyl-2,5-dimethyl cyclohexane.

1. 4-ethyl-3-propylhept-1-ene.
2. 3-chloro-4-cyclopropyl-1,2 cyclobutandiol.
3. Butan-2, 3-diol.

III > II > IV > I is increasing order of base strength because

is order of acidic character. Greater the acidic strength, weaker will be conjugate base and vice-versa.

1. Free radical.
2. Carbanion.
3. Carbocation.
4. Carbene.

1.  

2.  

3.  

1.  

2.  

(B) is more stable because it does not involve change separation.

1.  

2.  

The given carbocation has two resonance structures. Structure (II) is more stable because both the carbon atoms and the oxygen atom have an octet of electrons.

2.  

The liquid (A) is expected to come out first in the distillate. On boiling the vapours of lower boiling component are formed first. The vapours are condensed to get the liquid in a receiver.

Delocalisation: Delocalisation means that pairs of bonding electrons extend over three or more atoms and belong to the whole molecule. Delocalised orbital are much larger than the localised it orbital and are therefore more stable.

The reactive intermediates are those chemical species which are produced during the course of the reaction. There are many reactive intermediate, three of which are carbocation, carbanion and the free radical.
Carbocation and carbanion are generated by the heterolytic bond fission while free radicals are generated by homolytic bond fission.

1. Fractional distillation because the boiling points of the two liquids differ by only 10°.
2. Simple distillation because the boiling points of the two liquids differ much.

Simple distillation can be used because the two compounds have a difference of more than 20° in their boiling points and therefore, both the liquids can be distilled without any decomposition.

1. Elimination (Dehydration).
2. Rearrangement addition (More alkyl substituted alkenes are more stable).
3. Rearrangement substitution (3° carbocation is more stable).

1. 2, 3-dimethyl-4-oxo pent-2-en-oic acid.
2. 1, 3, 3-trimethyl cyclohex-1-ene.

The two isomers which differ in the position of the functional group on the carbon skeleton are called position isomers and the phenomenon is known as position isomerism. Thus, A and B may be regarded as position isomers but they are not considered as metamers since metamers are those isomers which have different number of carbon atoms on either side of the functional group. But here, the number of carbon atoms on either side of sulphur atom (functional group) is the same, i.e. 1 and 3.

1. Methyl alcohol.
2. Ethyl alcohol.
3. Diethyl ether.
4. Acetic acid.
5. P-xylene.

1.  

2.  

In both these molecules, carbon acquiring +ve charge is the electrophilic centre.

1. They are metamers.
2. They are functional isomers.

1.  

2.  

Benzoic acid is sparingly soluble in water at room temperature but appreciably soluble at higher temperature. The solution is concentrated to get a nearly saturated solution. On cooling the solution, pure compound crystallises out.