The oxide of alkaline earth which is covalent and insoluble in water is ……… .

Explanation

To solve the question, "The oxide of alkaline earth which is covalent and insoluble in water is ………," we can follow these steps:

### Step 1: Understand the Alkaline Earth Metals
Alkaline earth metals are found in Group 2 of the periodic table. They include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).

### Step 2: Identify the Oxides of Alkaline Earth Metals
The oxides of alkaline earth metals include:
- Beryllium oxide (BeO)
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