Question

The theory of strain less ring was explained by
A) Baeyer
B) Sachse and Mohr
C) Kekule
D) Erlenmeyer

Answer 1

To answer this question, you should recall the concept of the stainless ring. Strain in organic chemistry is defined as an increase in molecular potential energy due to electron repulsion or a deviation from ideal geometry.

Complete step by step solution:
Strain theory was the idea given by the chemist Adolf von Baeyer that the stability of carbocyclic compounds. Carbocyclic compounds are defined as the compounds those of which the molecular structure includes one or more rings of carbon atoms) depends on the amount by which the angles between the chemical bonds deviate from the value $\left( {109^{\circ} 28^{\prime} } \right)$ observed in compounds not containing such rings.
The amount of deviation is calculated from the strain to assess the stability of the ring: the greater the strain, the less stable is the ring. He gave the idea that these carbocyclic rings are planar and concluded that strain exists in three- and four-membered rings and in rings of six or more atoms, the strain increasing with the size of the ring. The least strain will be observed in the ring containing five carbon atoms which is cyclopentane, and the bond angles are $108^\circ$.

Hence, the correct option is option A.

Note:
H. Sachse proposed that rings containing six or more atoms the strain can be relieved completely if the ring is not planar but puckered, as in the so-called chair and boat conformations of cyclohexane. These large rings should then be as stable as those of five atoms—a conclusion that has been verified experimentally. This has been observed that there is no notable difference concerning strain between the stability of cyclic triacontane, which contains 30 atoms in the ring, and that of cyclopentane which has only 5 carbon atoms.