Write the structure of a d-aldohexose that gives a meso compound on treatment with nabh4 in water.

Explanation:

Meso compounds are optically inactive stereoisomers. Despite of having chiral carbon, they do not show  optical activity because it has a plane of symmetry in its structure itself. It is superposable on its mirror image.

Aldo sugars on reaction which reducing agents such as , NaBH₄ reduces the carbonyl group in the sugar to alcohol and gives corresponding alditol.

The D- aldohexose which on reduction gives a meso alditol are allose and galactose.

The structure is shown in the image below. Thus, in allitol and galactitol formed have internal plane of symmetry which makes the optically inactive.

what is the average time it took the car to travel 0.25 meters?

⇒ 2.23 seconds

what is the average time it took the car to travel 0.50 meters?

⇒ 3.13 seconds