O level Chemistry Identification of ions and gases

Methylamine (CH₃NH₂) undergoes the following reaction in water. Which is/are true about aqueous methylamine?

• It turns litmus paper blue

• It consists of CH₃NH₃⁺ and OH^- ions only

• It forms a blue precipitate with copper(II) sulfate

The best substance that can be used to differentiate hydrochloric acid and nitric acid solutions is...

• zinc metal

• barium nitrate solution

• silver nitrate solution

• sodium carbonate solution

What can compound X be?

• aluminium carbonate

• calcium carbonate

• zinc carbonate

• lead (II) sulfate

An excess of NaOH is added to an aqueous solution of salt L and boiled. Ammonia gas is only given off after aluminium foil is added to the hot solution. What could be salt L?

• Ammonium chloride

• Ammonium nitrate

• Sodium chloride

• Sodium nitrate

When sodium hydroxide solution is added to a solution containing potassium chloride and copper (II) nitrate, which of the following ions will decrease most in concentration?

• Cu²⁺

• K⁺

• NO^3-

• Cl^-

Excess dilute sulfuric acid was added to a fixed volume of aqueous barium hydroxide. Which graph best represents the variation in the total number of mobile ions present in the solution?

• 
• 
• 
• 

Arsine (AsH₃) is a gas that behaves like ammonia. Which of the following ions are produced when Arsine dissolves in water?

• AsH⁺ and H⁺

• AsH₃⁺ and OH^-

• AsH₄⁺ and H+

• AsH₄⁺ and OH^-

The diagram shows the results of an electrolysis using inert electrodes. Which of the following could be liquid R?

• aqueous silver nitrate

• aqueous sodium carbonate

• concentrated hydrochloric acid

• molten magnesium iodide

Aqueous hydrogen peroxide decomposes readily to form oxygen in the presence of manganese (IV) oxide as a catalyst. This reaction was used to produce and collect oxygen as shown in the diagram. Which substance could have contaminated the first few test tubes of collected gas?

• chlorine

• hydrogen peroxide

• manganese (IV) oxide

• nitrogen

Which pair of solutions will show no visible change when mixed?

• Barium nitrate and hydrochloric acid

• Copper(II) sulfate and lead(II) nitrate

• magnesium chloride and sodium carbonate

• zinc and iron(II) sulfate