Question

Identify the cation present in chlorophyll in green plants.

• A. \(\text{Mg}^{2+}\)
• B. \(\text{Ca}^{2+}\)
• C. \(\text{Fr}^+\)
• D. \(\text{Na}^+\)

Hint:

Chlorophyll has magnesium at the centre of its porphyrin ring.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Chlorophyll is the green pigment that captures light in plants. A metal ion sits at the centre of a ring structure called porphyrin.

Step 2: Detailed Explanation:
The metal ion at the centre is magnesium, as \(\text{Mg}^{2+}\). About 2.7 percent of chlorophyll is magnesium by mass.

Step 3: Why the other options are wrong.
\(\text{Ca}^{2+}\) is found in bones, teeth and plant cell walls. \(\text{Na}^+\) is an electrolyte in animal cells. \(\text{Fr}^+\) is a radioactive element which is not biological.

Final Answer:
The cation is magnesium, option (A). \[ \boxed{\text{Mg}^{2+}} \]