This question is about some elements in Group 7 and their compounds - AQA - A-Level Chemistry - Question 6 - 2022 - Paper 1

The equation for the reaction is:

$Cl_2 + H_2O \rightarrow HCl + HClO$

This is a redox (reduction-oxidation) reaction as chlorine undergoes reduction and oxidation simultaneously. In this reaction, one chlorine atom gains electrons to form chloride ions (Cl-) while the other loses electrons to form hypochlorous acid (HClO), showing a transfer of electrons.

The student would observe a brown solution or black solid forming, indicating the displacement reaction.

The ionic equation for the reaction between chlorine and sodium iodide is:

$Cl_2 + 2I^- \rightarrow 2Cl^- + I_2$

The equations for the formation of sulfur-containing products when sodium iodide reacts with sulfuric acid are:

1. $H_2SO_4 + 2NaI \rightarrow Na_2SO_4 + I_2 + H_2O$
2. $H_2SO_4 + 2NaI \rightarrow Na_2SO_4 + SO_2 + 2 HI$

In this reaction, sulfuric acid acts as an oxidizing agent, facilitating the oxidation of iodide ions (I-) to iodine (I2) or sulfur dioxide (SO2).

The identity of the sodium halide is sodium iodide (NaI).

The identity of the gas is chlorine (Cl2).

The ionic equation for the formation of chlorine gas from sodium iodide is:

$2NaI + Cl_2 \rightarrow 2Na^+ + 2Cl^- + I_2$

The shape of the ClF2- ion is linear with two bonded pairs and three lone pairs on the central chlorine atom.

The ClF2- ion has a linear shape due to the presence of three lone pairs of electrons that repel each other and the two bonded pairs of electrons, resulting in a geometry that minimizes repulsion.

The bond angle in the ClF2- ion is approximately 180 degrees.

The equation for the extraction of titanium from titanium(IV) chloride is:

$TiCl_4 + 2Mg \rightarrow Ti + 2MgCl_2$