Theory of ionisation was given by

Options

A. Rutherford
B. Faraday
C. Graham
D. Arrhenius

Explanation

**Step-by-Step Solution:**

1. **Identify the Question:** The question asks who proposed the theory of ionization.

2. **Recall Historical Context:** The theory of ionization is a significant concept in chemistry that explains how substances dissociate into ions when dissolved in water.

3. **Identify the Scientist:** The theory of ionization was proposed by a Swedish scientist named Svante Arrhenius in the year 1887.

4. **Explain the Theory:** Svante Arrhenius described that when acids are dissolved in water, they dissociate into charged particles known as ions. For example, an acid will produce hydrogen ions (H⁺), while bases will produce hydroxide ions (OH⁻).

5. **Conclusion:** Therefore, the answer to the question is Svante Arrhenius.

**Final Answer:** The theory of ionization was given by Svante Arrhenius.

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