Identify each of the following as D or L:

The structure is

We have to find that the isomer.

In this problem, we have to identify given structures as D or L.

The difference between $D$and $L$isomers is in the position of the -$OH$group in the penultimate carbon atom. The $OH$group in the $D$isomer of the penultimate carbon is on the right side, and in $L$isomer is on the left side. In the Figure below, we can see examples of $D$and $L$isomers on glyceraldehyde.

In this example the numbering starts from the top carbon atom (with the hydroxy group), which means that the penultimate carbon has the $OH$group on the right side, which means that this structure is a $D$isomer.

The structure is

We have to find the isomer

In this problem, we have to identify given structures as $L$or $D$.

The difference between $L$and $D$isomers is in the position of the $-OH$group in the penultimate carbon atom. The $OH$in the $D$isomer of the penultimate carbon is on the right side, and in $L$isomer is on the left side. In the Figure below, we can see examples of $D$and $L$isomers on glyceraldehyde.

In this example, the $OH$group is on the right side, which means that this structure is a $D$isomer.

The structure is

We have to find the isomer.

In this problem, we have to identify given structures as $D$or $L$.

The difference between $L$and $D$isomers is in the position of the - $OH$group in the penultimate carbon atom. The $OH$group in the $D$isomer of the penultimate carbon is on the right side, and in $L$isomer is on the left side. In the Figure below, we can see examples of $D$and $L$isomers on glyceraldehyde.

In this example, the $OH$group is on the left side, which means that this structure is a $L$isomer.