Question

chrome plating is commonly used in vehicle manufacturing for both corrosion resistance and aesthetics. a custom shop is preparing to chrome plate a part for a clients car. a current is applied to a chromium(iii) nitrate solution. how many moles of electrons are transferred during the reduction of chromium? ? mol e⁻

Explanation:

Step1: Determine the oxidation state of Cr in chromium(III) nitrate

In chromium(III) nitrate, the formula is \(Cr(NO_3)_3\). The nitrate ion (\(NO_3^-\)) has a charge of -1. Let the oxidation state of Cr be \(x\). Then, for the compound to be neutral: \(x + 3\times(-1)=0\), so \(x = + 3\).

Step2: Determine the reduction half - reaction

The reduction of chromium(III) ( \(Cr^{3+}\)) to chromium metal (Cr) is given by the half - reaction: \(Cr^{3+}+3e^-
ightarrow Cr\). This means that for each mole of \(Cr^{3+}\) that is reduced to Cr, 3 moles of electrons are transferred.

Answer:

3