What is the formal charge on carbon atom in $\mathrm{CO}_3^{2-}$ ion?

What is the formal charge on carbon atom in $\mathrm{CO}_3^{2-}$ ion?
  1. -2
  2. -4
  3. +4
  4. zero

Solution

$\begin{aligned} & \text { Formal charge } e=\left[\begin{array}{c} \text { Total no. of valence } \\ \mathrm{e}^{-} \text {in free state } \end{array}\right]-\left[\begin{array}{c} \text { Total no. of lone } \\ \text { pair electrons } \end{array}\right]-\frac{1}{2}\left[\begin{array}{c} \text { no. of bonding electrons } \\ \text { on that particular atom } \end{array}\right] \\ & =4-0-\frac{1}{2} \times 8=0 \\ & \end{aligned}$

Asked in: MHT CET 2021 (21 Sep Shift 1)

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