The oxidation states of nitrogen in NO, NO₂, N₂O and NO$_3^ -$ are in the order of :

<p>To determine the oxidation states of nitrogen in each compound, we consider the overall charge of the compound and the known oxidation states of other elements involved, typically oxygen.</p> <p><strong>NO (Nitric Oxide)</strong>:</p> <p><p>Oxygen generally has an oxidation state of $-2$.</p></p> <p><p>Let the oxidation state of nitrogen in NO be $x$.</p></p> <p><p>The equation: $x + (-2) = 0$.</p></p> <p><p>Solving for $x$, we find $x = +2$.</p></p> <p><strong>NO$_2$ (Nitrogen Dioxide)</strong>:</p> <p><p>Oxygen has an oxidation state of $-2$.</p></p> <p><p>Let the oxidation state of nitrogen be $x$.</p></p> <p><p>The equation: $x + 2(-2) = 0$.</p></p> <p><p>Solving for $x$, we find $x = +4$.</p></p> <p><strong>N$_2$O (Dinitrogen Monoxide or Nitrous Oxide)</strong>:</p> <p><p>Oxygen has an oxidation state of $-2$.</p></p> <p><p>Let each nitrogen atom have an oxidation state of $x$.</p></p> <p><p>The equation: $2x + (-2) = 0$.</p></p> <p><p>Solving for $x$, we find $x = +1$.</p></p> <p><strong>NO$_3^-$ (Nitrate Ion)</strong>:</p> <p><p>Oxygen has an oxidation state of $-2$.</p></p> <p><p>The overall charge of the ion is $-1$.</p></p> <p><p>Let the oxidation state of nitrogen be $x$.</p></p> <p><p>The equation: $x + 3(-2) = -1$.</p></p> <p><p>Solving for $x$, we find $x = +5$.</p></p> <p>Therefore, the oxidation states of nitrogen are:</p> <p><p>NO: $+2$</p></p> <p><p>NO$_2$: $+4$</p></p> <p><p>N$_2$O: $+1$</p></p> <p><p>NO$_3^-$: $+5$</p></p> <p>The order of oxidation states from highest to lowest is:</p> <p>NO$_3^-$ ($+5$) &gt; NO$_2$ ($+4$) &gt; NO ($+2$) &gt; N$_2$O ($+1$)</p> <p>Thus, the correct option is:</p> <p>Option D</p> <p>NO$_3^-$ &gt; NO$_2$ &gt; NO &gt; N$_2$O</p>