Chemistry 0620 · IGCSE · Electrolysis

Electrolysis — practice question

Sodium and fluorine react together to make sodium fluoride, NaF.
(a)[2]

Write the chemical equation for the reaction.

(b)[3]

Sodium fluoride is an ionic compound. Finish the diagram to show the electron arrangement in the outer shells of the ions found in sodium fluoride. Show the charge on each ion.

(c(i))[2]

State what the term electrolysis means.

(c(ii))[2]

Name the products produced at the positive electrode (anode) and the negative electrode (cathode) during electrolysis of dilute aqueous sodium fluoride.

(d(i))[2]

Name the products obtained at the positive electrode (anode) and the negative electrode (cathode) during electrolysis of molten sodium fluoride.

(d(ii))[1]

Write the ionic half-equation for the process at the negative electrode (cathode).

(e)[1]

Complete the dot-and-cross diagram to display the electron arrangement in a fluorine molecule, $\text{F}_2$. Include only the outer electrons.

(f(i))[2]

Deduce the physical state of fluorine at $-195^\circ\text{C}$. Use the table data to explain your answer.

(f(ii))[3]

Explain, in terms of structure and bonding, why sodium fluoride melts at a much higher temperature than fluorine. Your answer should mention the kind of particles held by the attractive forces, the kinds of attraction between particles, and how strong those attractions are compared with each other.

Worked solution & mark scheme

This 18-mark question has a full step-by-step worked solution and mark scheme. One marking point: Correct balanced equation: 2Na + F2 → 2NaF

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