Chlorine, chlorate(I) & water treatment

Equal amounts of three Period 3 elements are added to separate 100 cm³ samples of water.

Which list is correct when the solutions formed from these elements are arranged in order of decreasing pH?

This question is about chlorine.

Give an equation to show how chlorine forms an acidic solution in water.

Give an equation for the reaction between chlorine and cold, dilute aqueous sodium hydroxide.

In acidic conditions, ClO₃^– ions oxidise Cl^– ions to form Cl₂

Deduce a half-equation for the oxidation of Cl^– to Cl₂

Deduce a half-equation for the reduction of ClO₃^– to Cl₂

Deduce the overall equation for this reaction.

Half-equation for the oxidation of Cl^– to Cl₂

Half-equation for the reduction of ClO₃^– to Cl₂

Overall equation

Give the equation for the reaction of solid sodium chloride with concentrated sulfuric acid.

State the role of the chloride ions in this reaction.

Equation

Draw the shape of the Cl₃^– ion. Include any lone pairs of electrons that influence the shape.

Chlorine forms an ion with the Group 3 element thallium (T l).

State and explain the bond angle in TlCl₂⁺

This question is about some elements in Group 7 and their compounds.

Chlorine is added to some drinking water supplies to decrease the risk of people suffering from diseases such as cholera.

State why the amount of chlorine added must be controlled.

Give an equation for the reaction of chlorine with water to form a solution containing two acids.

Explain, with reference to electrons, why this is a redox reaction.

Equation

A student bubbles chlorine gas through a solution of sodium iodide.

State the observation the student would make.

Give an ionic equation for the reaction.

Ionic equation

The student adds a few drops of concentrated sulfuric acid to a small amount of solid sodium iodide.

Two gaseous sulfur-containing products are formed.

Give an equation for the formation of each of these sulfur-containing products.

State the role of sulfuric acid in the formation of these products.

Equation 1

Equation 2

The student adds a few drops of acidified silver nitrate solution to a solution of an unknown impure sodium halide. The student observes bubbles of gas and a colourless solution. The student bubbles the gas through calcium hydroxide solution and a white precipitate forms.

Deduce the identity of the sodium halide.

Suggest the identity of the gas.

Give an ionic equation for the formation of this gas from the impurity.

Identity of sodium halide

Ionic equation

The ClF₂⁺ ion contains two different Group 7 elements.

Use your understanding of the electron pair repulsion theory to draw the shape of this ion.

Include any lone pairs of electrons that influence the shape.

Explain why the ion has the shape you have drawn.

Suggest a value for the bond angle in the ion.

Shape

Magnesium is used in the extraction of titanium from titanium(IV) chloride.

Give an equation for this reaction.

Tschermigite is a hydrated, water-soluble mineral, with relative formula mass of 453.2

The formula of tschermigite can be represented as M.xH₂O, where M represents all the ions present.

Table 4 shows its composition by mass.

In an analysis, it is found that the mineral contains the ions NH₄⁺, Al³⁺ and SO₄²

Calculate the empirical formula of tschermigite and the value of x in M.xH₂O

Describe the tests, with their results, including ionic equations, that would confirm the identities of the ions present.

Which shows the major product(s) formed when chlorine reacts with cold, dilute, aqueous sodium hydroxide?

What is the most suitable reagent for detecting the presence of carbonate ions in the presence of an excess of sulfate ions?

Chlorine reacts with cold, dilute, aqueous sodium hydroxide.

Which is a complete list of the products?

Which observation would confirm that ammonia gas is released when solid ammonium chloride is warmed with solid calcium hydroxide?