Which of the following compounds contains nitrogen with an oxidation number of +5?

• A. NO_2
• B. NO_3^-
• C. N_2O
• D. NH_3

Answer: (B)

Verified step by step guidance

1. Recall that the oxidation number of nitrogen can vary depending on the compound, and it is determined by assigning oxidation states to each atom such that the sum equals the overall charge of the molecule or ion.
2. For each compound, assign oxidation numbers to oxygen and hydrogen first, since their typical oxidation states are well known: oxygen is usually -2, and hydrogen is usually +1.
3. Calculate the oxidation number of nitrogen in each compound by setting up an equation where the sum of oxidation numbers equals the overall charge of the compound or ion.
4. For example, in the nitrate ion \(\mathrm{NO_3^-}\), let the oxidation number of nitrogen be \(x\). Since each oxygen is -2 and there are three oxygens, the equation is: \(x + 3(-2) = -1\).
5. Solve the equation for \(x\) to find the oxidation number of nitrogen in each compound, and identify which one has nitrogen with an oxidation number of +5.