n monosaccharide $\underset{Q}{\stackrel{P}{\rightleftharpoons}}$ polysaccharide -n water. In the process above, P and Q respectively represent

Analysis

The question asks us to identify the chemical processes represented by P and Q in the conversion between monosaccharides and polysaccharides.

Concept Explanation

• Monosaccharides are simple sugars (like glucose).
• Polysaccharides are complex carbohydrates (like starch or cellulose) made of many monosaccharide units linked together.
• Condensation Reaction: This is a process where two or more molecules combine to form a larger molecule, usually with the loss of a small molecule like water ($H_2O$). When many monosaccharides join to form a polysaccharide, water is removed.
• Hydrolysis: This is the reverse process. It involves the breaking down of a complex molecule (like a polysaccharide) into simpler units (monosaccharides) by the addition of water.

Step-by-Step Solution

1. Analyze the forward reaction (P): The equation shows $n$ monosaccharides becoming a polysaccharide and losing $n$ water molecules. This is the definition of condensation (specifically, dehydration synthesis). Therefore, P = Condensation.
2. Analyze the reverse reaction (Q): The equation shows the polysaccharide reacting with water to break back down into $n$ monosaccharides. This is the definition of hydrolysis (literally "splitting with water"). Therefore, Q = Hydrolysis.
3. Match with the options: We are looking for the pair (P, Q) which corresponds to (Condensation, Hydrolysis).

Conclusion

Comparing our findings to the given options:

• Option A: Condensation and hydrolysis (Matches our derivation).

Exam Tip

Think of "Condensation" as "condensing" or squeezing things together to form a bigger structure (releasing water), and "Hydrolysis" as "hydro" (water) + "lysis" (breaking/splitting). Whenever you see water being added to break a bond, it is always hydrolysis!