Question

How do multiple bonds introduce rigidity into molecules?


what is meant by rigidity??

Answer 1

Stick a pin (representing a single bond) into a ball. Then hold the pin and rotate the ball about the single pin and you will see that there is free rotation about the axis (the pin). That is, you can turn the ball about the axis quite easily. Now stick a second pin about a quarter inch or so from the first pin into the ball. Hold the two pins at the free end and try to rotate the ball. You can't do it because the ball is being held in two spots instead of one. That's the way double or triple bonds work versus single bonds. We say there is free rotation about a single bond but rotation about a multiple bond is hindered.