Ontario Grade 9 Science Class Practice Exam

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What is the process called when ammonia (NH3) is converted to nitrate ions (NO3)-?

Nitrification
Denitrification
Assimilation
Ammonification

The correct answer is: Nitrification

Nitrification is the process of converting ammonia (NH3) to nitrate ions (NO3)- by bacteria. This process can occur in soil or water, and it is an essential part of the nitrogen cycle. Option B, denitrification, is the opposite process and converts nitrate ions into nitrogen gas. Option C, assimilation, refers to the uptake of nitrogen by plants and incorporation into their tissues. Option D, ammonification, is the process of breaking down nitrogen-containing organic compounds into ammonia by bacteria and fungi. Therefore, options B, C, and D are not correct as they do not involve the conversion of ammonia to nitrate ions.