Зачеркни формулу лишнего вещества

• \(\mathrm{NO\_2}\)
• \(\mathrm{Fe\_2O\_3}\)
• \(\mathrm{SiO\_2}\)
• \(\mathrm{CaO}\)
• \(\mathrm{Cu(OH)\_2}\)
• \(\mathrm{P\_2O\_5}\)