Question

carrot slices placed in a 0.2 m salt solution for several hours become flaccid (limp). carrot slices placed in fresh water for several hours become turgid (stiff). from this we can deduce that ...

the fresh water and the salt solution are both hypertonic to the cells of the carrot slices.

the fresh water and the salt solution are both hypotonic to the cells of the carrot slices.

the fresh water is hypertonic and the salt solution is hypotonic to the cells of the carrot slices.

the fresh water is hypotonic and the salt solution is hypertonic to the cells of the carrot slices.

the fresh water is isotonic and the salt solution is hypertonic to the cells of the carrot slices.

Explanation:

To solve this, we analyze osmosis:

• When a cell is in a hypotonic solution (lower solute concentration than the cell), water enters the cell, making it turgid (stiff). Fresh water has less solute than carrot cells, so water enters carrot cells (they become turgid) → fresh water is hypotonic to carrot cells.
• When a cell is in a hypertonic solution (higher solute concentration than the cell), water leaves the cell, making it flaccid (limp). A 0.2 M salt solution has more solute than carrot cells, so water leaves carrot cells (they become flaccid) → salt solution is hypertonic to carrot cells.

Now, evaluate the options:

• Option 1: Both hypertonic? Fresh water can’t be hypertonic (carrot becomes turgid, not flaccid). Eliminate.
• Option 2: Both hypotonic? Salt solution can’t be hypotonic (carrot becomes flaccid, not turgid). Eliminate.
• Option 3: Fresh water hypertonic, salt solution hypotonic? Contradicts observations (fresh water causes turgidity, salt causes flaccidity). Eliminate.
• Option 4: Fresh water hypotonic (water enters, turgid), salt solution hypertonic (water leaves, flaccid). Matches observations.
• Option 5: Fresh water isotonic? If isotonic, no net water movement (carrot wouldn’t become turgid). Eliminate.

Answer:

D. the fresh water is hypotonic and the salt solution is hypertonic to the cells of the carrot slices.