<Dl> <Dd> 2 NO + 2 NH 3 + ⁄ O 2 → 2 N 2 + 3 H O and </Dd> <Dd> 3 NO 2 + 4 NH 3 → 3 ⁄ N 2 + 6 H O </Dd> </Dl> <Dd> 2 NO + 2 NH 3 + ⁄ O 2 → 2 N 2 + 3 H O and </Dd> <Dd> 3 NO 2 + 4 NH 3 → 3 ⁄ N 2 + 6 H O </Dd> <P> The overall reduction of NO x by urea is: </P>

What kind of urea is used in def