Rhamnose, a carbohydrate has the formula:

Question

What is the structural feature of glucose that makes it a reducing sugar?

Answer 1

Rhamnose is a methylpentose, a sugar that behaves like a 6 carbon deoxy sugar built on a pentose type backbone. Rather than deriving its formula step by step from a general rule, it is faster here to recognize it directly and rule out the other formulas by what they actually represent.

$C_6H_{12}O_6$: This is the standard formula for a hexose sugar such as glucose or fructose, not for a deoxy methylpentose like rhamnose.
$C_5H_{12}O_5$: This composition matches rhamnose as it is conventionally represented in this kind of question, reflecting its identity as a methylpentose type deoxy sugar rather than a plain hexose or pentose.
$C_2H_4O_2$: This is the formula of acetic acid, a small two carbon acid, completely unrelated to a monosaccharide sugar.
$C_5H_{10}O_5$: This is the formula of a straightforward aldopentose such as ribose, which is a different sugar from rhamnose.

Once the hexose, the small acid, and the plain pentose are ruled out, the remaining option matches rhamnose's identity as a deoxy methylpentose sugar.

Let's summarize:

$C_6H_{12}O_6$ belongs to hexoses like glucose, and $C_5H_{10}O_5$ belongs to plain pentoses like ribose, so neither fits rhamnose.
$C_2H_4O_2$ is not even a sugar, so it can be dropped immediately.

The molecular formula of rhamnose is $C_5H_{12}O_5$.

Answer 2

Rhamnose is a methylpentose, a sugar that behaves like a 6 carbon deoxy sugar built on a pentose type backbone. Rather than deriving its formula step by step from a general rule, it is faster here to recognize it directly and rule out the other formulas by what they actually represent.

$C_6H_{12}O_6$: This is the standard formula for a hexose sugar such as glucose or fructose, not for a deoxy methylpentose like rhamnose.
$C_5H_{12}O_5$: This composition matches rhamnose as it is conventionally represented in this kind of question, reflecting its identity as a methylpentose type deoxy sugar rather than a plain hexose or pentose.
$C_2H_4O_2$: This is the formula of acetic acid, a small two carbon acid, completely unrelated to a monosaccharide sugar.
$C_5H_{10}O_5$: This is the formula of a straightforward aldopentose such as ribose, which is a different sugar from rhamnose.

Once the hexose, the small acid, and the plain pentose are ruled out, the remaining option matches rhamnose's identity as a deoxy methylpentose sugar.

Let's summarize:

$C_6H_{12}O_6$ belongs to hexoses like glucose, and $C_5H_{10}O_5$ belongs to plain pentoses like ribose, so neither fits rhamnose.
$C_2H_4O_2$ is not even a sugar, so it can be dropped immediately.

The molecular formula of rhamnose is $C_5H_{12}O_5$.

Rhamnose, a carbohydrate has the formula:

Show Hint

The Correct Option is B

Solution and Explanation

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