A metal forms the fluoride MF3. Electrolysis of the molten fluoride by a current of 3.86 A for 16.2 minutes deposits 1.25 g of the metal. Ca

Question

A metal forms the fluoride MF3. Electrolysis of the molten fluoride by a current of 3.86 A for 16.2 minutes deposits 1.25 g of the metal. Calculate the molar mass of the metal.

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Eirian 4 years 2021-07-19T05:34:14+00:00 1 Answers 164 views 0

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  1. Ben
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    2021-07-19T05:35:55+00:00
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    Answer: The molar mass of the metal is 96.45 g/mol

    Explanation:

    The fluoride of the metal formed is MF_3

    The oxidation half-reaction follows:

    M\rightarrow M^{3+}+3e^-

    Calculating the theoretical mass deposited by using Faraday’s law, which is:

    m=\frac{M\times I\times t(s)}{n\times F}       ……(1)

    where,

    m = actual mass deposited = 1.25 g

    M = molar mass of metal = ?

    I = average current = 3.86 A

    t = time period in seconds = 16.2 min = 972 s            (Conversion factor: 1 min = 60 sec)

    n = number of electrons exchanged = 3mol^{-1}

    F = Faraday’s constant = 96500 C

    Putting values in equation 1, we get:

    1.25g=\frac{M\times 3.86A\times 972s}{3mol^{-1}\times 96500 C}\\\\M=\frac{1.25g\times 3mol^{-1}\times 96500 C}{3.86A\times 972s}\\\\M=96.45g/mol

    Hence, the molar mass of the metal is 96.45 g/mol

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