Question #8462f

1 Answer
Feb 21, 2017

Answer:

Here's what I get.

Explanation:

Sodium is the only Group 1 element that gives a yellow flame colour.

Flame colors
(Adapted from www.pinterest.com)

A sodium atom in an unexcited state has the electron configuration #"1s"^2 "2s"^2 "2p"^6 "3s"# but, within the flame, there will be many atoms with different excited states.

The bright orange-yellow flame colour results when electrons fall back from the #"3p"# level to their normal #"3s"# level.

The most likely candidate for the green gas is chlorine.

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Sodium reacts vigorously with chlorine to form the white solid, sodium chloride.

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The melting point of the ionic solid is 801 °C.

The equation for the reaction is

#"2Na(s)" + underbrace("Cl"_2"(g)")_color(red)("green gas") → underbrace("2NaCl(s)")_color(red)("white solid")#

A sodium ion, #"Na"^"+"#, is just the right size to fit in the cavity of 15-crown-5, where becomes strongly attracted to the oxygen atoms.

15-Crown-5
(Adapted from OChemPal)

The crown ether is soluble in organic solvents, so the complex is often used to make sodium salts soluble in organic solvents.