Question

The correct sequence of the oxidation state of underlined elements is
$Na_{2}\left[\frac{Fe}{ }\left(CN\right)_{5}N O\right]$, $K_{2} \frac{Ta}{ }F_{7}$, $Mg_{2}P_{2}O_{7}$, $Na_{2} \frac{S_{4}}{ }O_{6}$, $\frac{N_{3}}{ }H $

• A. $+3$, $+5$, $+5$, $+2.5$, $-\frac{1}{3} $
• B. $+5$, $+3$, $+5$, $+3$, $+\frac{1}{3} $
• C. $+3$, $+3$, $+5$, $+5$, $-\frac{1}{3} $
• D. $+5$, $+5$, $+3$, $+2.5$ $+\frac{1}{3} $

Answer 1

Answer: (A)

$Na_{2}\left[Fe\left(CN\right)_{5}N O\right]: + 2 + x + 5\left(-1\right) + 0 = 0$
$\Rightarrow x = +3$
$K_{2} \frac{Ta}{ }F_{7} : + 2 + x + \left(-7\right) = 0 \Rightarrow x = +5$
$Mg_{2}P_{2}O_{7} : + 4 + 2x + \left(-14\right) = 0 \Rightarrow x = +5$
$Na_{2} \frac{S_{4}}{ }O_{6} : + 2 + 4x + \left(-12\right) = 0$ or $4x = 10 \Rightarrow x = + 2.5$
$\frac{N_{3}}{ }H : 3x + 1 = 0\quad\Rightarrow \quad x = -\frac{1}{3}$