Electro Chemistry

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Oxidation is the process in which an atom or ion loses one or more electrons. For example, in the reaction: $$\mathrm{Na} \rightarrow \mathrm{Na}^{+} + e^{-}$$ Sodium loses an electron and undergoes…

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Reduction is the process in which an atom or ion gains one or more electrons. For example, in the reaction: $$\mathrm{Cl} + e^{-} \rightarrow \mathrm{Cl}^{-}$$ Chlorine gains an electron and undergo…

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A redox reaction is a chemical reaction in which both oxidation and reduction occur simultaneously. Example: $$\mathrm{Zn} + \mathrm{Cu}^{2+} \rightarrow \mathrm{Zn}^{2+} + \mathrm{Cu}$$ Here, Zn i…

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Oxidation number is the apparent charge on an atom in a molecule or ion, assuming all bonds are ionic. **Rules:** 1. Elemental form: 0 (e.g., O₂, Na) 2. Monatomic ion: same as charge (e.g., Na⁺ = +1)…

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Let oxidation number of S be x. H₂SO₄ is neutral. Oxidation of H = +1 (each), so 2×(+1) = +2 Oxidation of O = -2 (each), so 4×(-2) = -8 So: +2 + x - 8 = 0 → x = +6 Thus, oxidation number of S in H…

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Let oxidation number of N be x. Oxidation of O = -2 (each), so 3×(-2) = -6 Total charge = -1 So: x - 6 = -1 → x = +5 Thus, oxidation number of N in NO₃⁻ is **+5**.

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Let oxidation number of Cr be x. Oxidation of O = -2 (each), so 7×(-2) = -14 Total charge = -2 So: 2x - 14 = -2 → 2x = 12 → x = +6 Thus, oxidation number of Cr in Cr₂O₇²⁻ is **+6**.

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**Step 1:** Write skeletal equation: $$\mathrm{P} + \mathrm{HNO}_3 \rightarrow \mathrm{HPO}_3 + \mathrm{NO} + \mathrm{H}_2\mathrm{O}$$ **Step 2:** Assign oxidation numbers: P: 0 → +5 (increase by 5…