Identifying Ions

When compound \(X\) is heated, it changes colour from green to black. Compound \(Y\) is formed and a gas is given off which turns limewater milky.
What are \(X\) and \(Y\) ?

\[
\begin{array}{|c|c|c|}
\hline & \text { X } & Y \\
\hline \text { A } & \text { calcium carbonate } & \text { calcium oxide } \\
\text { B } & \text { copper carbonate } & \text { carbon } \\
\text { C } & \text { copper carbonate } & \text { copper oxide } \\
\text { D } & \text { copper sulfate } & \text { copper oxide } \\
\hline
\end{array}
\]

An aqueous cation reacts with aqueous sodium hydroxide to form a white precipitate.
The precipitate is insoluble in excess sodium hydroxide.
What is the aqueous cation?

A solution contains barium ions and silver ions. What could the anion be?

Which ion forms a green precipitate with aqueous sodium hydroxide that dissolves in an excess of aqueous sodium hydroxide?

A white precipitate is produced when small amounts of two colourless solutions are mixed together. Which pairs of solutions produce a white precipitate?

1. sodium hydroxide and zinc nitrate
2. sodium hydroxide and aluminium chloride
3. barium chloride and sulfuric acid
4. acidified barium nitrate and potassium sulfate

Salts \(X\) and \(Y\) are separately dissolved in water. Samples of the solutions obtained are separately tested with dilute hydrochloric acid and with aqueous sodium hydroxide.
In two of the tests, a gaseous product is formed. No precipitate is formed in any of the tests. What are salts \(X\) and \(Y\) ?

\[
\begin{array}{|c|c|c|}
\hline & \mathrm{X} & \mathrm{Y} \\
\hline \text { A } & \mathrm{AgNO}_3 & \mathrm{BaSO}_4 \\
\text { B } & \mathrm{BaSO}_4 & \mathrm{Na}_2 \mathrm{CO}_3 \\
\text { C } & \mathrm{Na}_2 \mathrm{CO}_3 & \mathrm{NH}_4 \mathrm{Cl} \\
\text { D } & \mathrm{NH}_4 \mathrm{Cl} & \mathrm{AgNO}_3 \\
\hline
\end{array}
\]

Aqueous sodium hydroxide is added to a solid, \(\mathrm{X}\), and the mixture is heated.
A green precipitate is formed and an alkaline gas is given off.
Which ions are present in \(X\) ?

Compound X is tested and the results are shown in the table.

Test: Aqueous sodium hydroxide is added and then heated gently
Result: gas given off which turns moist red litmus paper blue

Test: dilute hydrochloric acid is added
Result: effervescence, gas given off which turns limewater milky

Which ions are present in compound X?

Which of the following pairs of aqueous ions both react with dilute sulfuric acid to give a visible result?

The results of three tests on a solution of compound X are shown in the table.

Test: aqueous sodium hydroxide added
Result: white precipitate formed, soluble in excess

Test: aqueous ammonia added
Result: white precipitate formed, insoluble in excess

Test: acidified barium nitrate added
Result: white precipitate formed

What is compound X?

The results of three tests on a solution of compound X are shown.

Test: aqueous sodium hydroxide added
Result: white precipitate formed, soluble in excess

Test: aqueous ammonia added
Result: white precipitate formed, soluble in excess

Test: silver(I) nitrate added
Result: white precipitate formed

What is compound X?

1. Some barium iodide is dissolved in water.
2. Dilute sulfuric acid is added to the solution until no more precipitate forms. The precipitate, X, is filtered off.
3. Aqueous lead(II) nitrate is added to the filtrate and another precipitate, Y, forms.

What are the colours of precipitates X and Y?

Aqueous sodium hydroxide is added to a solid, X, and the mixture is heated.
A brown precipitate is formed and an alkaline gas is given off.
Which ions are present in X?

• A white solid is insoluble in water.
• When it is added to hydrochloric acid, bubbles of gas released.
• When excess aqueous ammonia is added to the solution formed, white precipitate produced and the white precipitate dissolve in excess aqueous ammonia

What is the white solid?

Some barium iodide is dissolved in water.
Aqueous lead(II) nitrate is added to the solution until no more precipitate forms. This precipitate, \(X\), is filtered off.
Dilute sulfuric acid is added to the filtrate and another precipitate, Y, forms. What are the colours of precipitates \(X\) and \(Y\) ?

\[
\begin{array}{|c|c|c|}
\hline & X & Y \\
\hline \text { A } & \text { white } & \text { white } \\
\text { B } & \text { white } & \text { yellow } \\
\text { C } & \text { yellow } & \text { white } \\
\text { D } & \text { yellow } & \text { yellow } \\
\hline
\end{array}
\]